Chrome reports UDP port blocked but netcat can connect

I am using Chrome browser 84.0.4147.89 (64-bit) and when I run the Chrome Connectivity Diagnostics I get the following error log for UDP port 19302-19309.

SUMMARY
Test Name: Hangouts Connectivity Test
Test ID: 12
Test result: Potential problem detected

CRITERIA
Hangouts blocked test returns a no problem verdict if: (1) a connection can be established to stun.l.google.com on any UDP port from 19302 to 19309 (2) A TCP connection can be established to apis.google.com, clients6.google.com, plus.google.com, and talkgadget.google.com
Hangouts blocked test returns a problem verdict if: (1) all UDP destination ports from 19302 to 19309 are blocked for stun.l.google.com (2) A TCP connection to any of the following hosts fails on port 443: apis.google.com, clients6.google.com, plus.google.com, talkgadget.google.com

SUPPORT DETAILS
https://support.google.com/a/answer/1279090

DETAILS
Tue Jul 21 2020 11:33:04 GMT-0500 (Central Daylight Time) – Setting UDP timeout length (msec): 10000
Tue Jul 21 2020 11:33:04 GMT-0500 (Central Daylight Time) – Creating a UDP socket, number / host / port: 30 / stun.l.google.com / 19302
Tue Jul 21 2020 11:33:04 GMT-0500 (Central Daylight Time) – Preparing to send UDP socket data with size (bytes): 20
Tue Jul 21 2020 11:33:04 GMT-0500 (Central Daylight Time) – Successfully sent data with size (bytes): 20
Tue Jul 21 2020 11:33:14 GMT-0500 (Central Daylight Time) – UDP connection failed and is blocked on destination port 19302
Tue Jul 21 2020 11:33:14 GMT-0500 (Central Daylight Time) – Setting UDP timeout length (msec): 10000
Tue Jul 21 2020 11:33:14 GMT-0500 (Central Daylight Time) – Creating a UDP socket, number / host / port: 31 / stun.l.google.com / 19303
Tue Jul 21 2020 11:33:14 GMT-0500 (Central Daylight Time) – Preparing to send UDP socket data with size (bytes): 20
Tue Jul 21 2020 11:33:14 GMT-0500 (Central Daylight Time) – Successfully sent data with size (bytes): 20
Tue Jul 21 2020 11:33:24 GMT-0500 (Central Daylight Time) – UDP connection failed and is blocked on destination port 19303
Tue Jul 21 2020 11:33:24 GMT-0500 (Central Daylight Time) – Setting UDP timeout length (msec): 10000
Tue Jul 21 2020 11:33:24 GMT-0500 (Central Daylight Time) – Creating a UDP socket, number / host / port: 32 / stun.l.google.com / 19304
Tue Jul 21 2020 11:33:24 GMT-0500 (Central Daylight Time) – Preparing to send UDP socket data with size (bytes): 20
Tue Jul 21 2020 11:33:24 GMT-0500 (Central Daylight Time) – Successfully sent data with size (bytes): 20
Tue Jul 21 2020 11:33:34 GMT-0500 (Central Daylight Time) – UDP connection failed and is blocked on destination port 19304
Tue Jul 21 2020 11:33:34 GMT-0500 (Central Daylight Time) – Setting UDP timeout length (msec): 10000
Tue Jul 21 2020 11:33:34 GMT-0500 (Central Daylight Time) – Creating a UDP socket, number / host / port: 33 / stun.l.google.com / 19305
Tue Jul 21 2020 11:33:34 GMT-0500 (Central Daylight Time) – Preparing to send UDP socket data with size (bytes): 20
Tue Jul 21 2020 11:33:34 GMT-0500 (Central Daylight Time) – Successfully sent data with size (bytes): 20
Tue Jul 21 2020 11:33:44 GMT-0500 (Central Daylight Time) – UDP connection failed and is blocked on destination port 19305
Tue Jul 21 2020 11:33:44 GMT-0500 (Central Daylight Time) – Setting UDP timeout length (msec): 10000
Tue Jul 21 2020 11:33:44 GMT-0500 (Central Daylight Time) – Creating a UDP socket, number / host / port: 34 / stun.l.google.com / 19306
Tue Jul 21 2020 11:33:44 GMT-0500 (Central Daylight Time) – Preparing to send UDP socket data with size (bytes): 20
Tue Jul 21 2020 11:33:44 GMT-0500 (Central Daylight Time) – Successfully sent data with size (bytes): 20
Tue Jul 21 2020 11:33:54 GMT-0500 (Central Daylight Time) – UDP connection failed and is blocked on destination port 19306
Tue Jul 21 2020 11:33:54 GMT-0500 (Central Daylight Time) – Setting UDP timeout length (msec): 10000
Tue Jul 21 2020 11:33:54 GMT-0500 (Central Daylight Time) – Creating a UDP socket, number / host / port: 35 / stun.l.google.com / 19307
Tue Jul 21 2020 11:33:54 GMT-0500 (Central Daylight Time) – Preparing to send UDP socket data with size (bytes): 20
Tue Jul 21 2020 11:33:54 GMT-0500 (Central Daylight Time) – Successfully sent data with size (bytes): 20
Tue Jul 21 2020 11:34:04 GMT-0500 (Central Daylight Time) – UDP connection failed and is blocked on destination port 19307
Tue Jul 21 2020 11:34:04 GMT-0500 (Central Daylight Time) – Setting UDP timeout length (msec): 10000
Tue Jul 21 2020 11:34:04 GMT-0500 (Central Daylight Time) – Creating a UDP socket, number / host / port: 36 / stun.l.google.com / 19308
Tue Jul 21 2020 11:34:04 GMT-0500 (Central Daylight Time) – Preparing to send UDP socket data with size (bytes): 20
Tue Jul 21 2020 11:34:04 GMT-0500 (Central Daylight Time) – Successfully sent data with size (bytes): 20
Tue Jul 21 2020 11:34:14 GMT-0500 (Central Daylight Time) – UDP connection failed and is blocked on destination port 19308
Tue Jul 21 2020 11:34:14 GMT-0500 (Central Daylight Time) – Setting UDP timeout length (msec): 10000
Tue Jul 21 2020 11:34:14 GMT-0500 (Central Daylight Time) – Creating a UDP socket, number / host / port: 37 / stun.l.google.com / 19309
Tue Jul 21 2020 11:34:14 GMT-0500 (Central Daylight Time) – Preparing to send UDP socket data with size (bytes): 20
Tue Jul 21 2020 11:34:14 GMT-0500 (Central Daylight Time) – Successfully sent data with size (bytes): 20
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – UDP connection failed and is blocked on destination port 19309
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – Setting TCP timeout length (msec): 10000
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – Creating a TCP socket, number / host / port: 38 / stun.l.google.com / 443
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – TCP connection established with host / port / status code: stun.l.google.com / 443 / 0
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – TCP connection succeeded on port 443 for host 443
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – Setting TCP timeout length (msec): 10000
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – Creating a TCP socket, number / host / port: 39 / apis.google.com / 443
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – TCP connection established with host / port / status code: apis.google.com / 443 / 0
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – Setting TCP timeout length (msec): 10000
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – Creating a TCP socket, number / host / port: 40 / talkgadget.google.com / 443
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – TCP connection established with host / port / status code: talkgadget.google.com / 443 / 0
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – Setting TCP timeout length (msec): 10000
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – Creating a TCP socket, number / host / port: 41 / clients6.google.com / 443
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – TCP connection established with host / port / status code: clients6.google.com / 443 / 0
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – Setting TCP timeout length (msec): 10000
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – Creating a TCP socket, number / host / port: 42 / hangouts.google.com / 443
Tue Jul 21 2020 11:34:24 GMT-0500 (Central Daylight Time) – TCP connection established with host / port / status code: hangouts.google.com / 443 / 0

But when I do netcat it tells me the ports are open and fine:

$ nc -v -u -z -w 3 stun.l.google.com 19302-19309
Connection to stun.l.google.com 19302 port [udp/*] succeeded!
Connection to stun.l.google.com 19303 port [udp/*] succeeded!
Connection to stun.l.google.com 19304 port [udp/*] succeeded!
Connection to stun.l.google.com 19305 port [udp/*] succeeded!
Connection to stun.l.google.com 19306 port [udp/*] succeeded!
Connection to stun.l.google.com 19307 port [udp/*] succeeded!
Connection to stun.l.google.com 19308 port [udp/*] succeeded!
Connection to stun.l.google.com 19309 port [udp/*] succeeded!

If I use a VPN then I don’t have any issues with blocked ports. So it is something on my local network that is causing this issue.

I have setup port forwarding for these ports and I have also tried disabling chrome://flags/#same-site-by-default-cookies, but nothing has resolved the issue.

What is keeping Connectivity Diagnostics from connecting to these UDP ports?