Pilot in gas water heater still goes out after replacing thermocouple

The pilot in my gas water heater (Aquamax 205) has been going out sporadically over the last 2 weeks. Yesterday, I replaced the thermocouple with a universal thermocouple and cleaned out the dust and soot from the burner area.

After installation, I also did the detergent test to make sure the gas connections are secure and not leaking.

I lighted the pilot and it appeared to work fine. A few hours later, I checked the pilot and it was out, so I relighted it. I got up this morning and checked it again and the pilot was out again.

The water heater was working really well with no issues before this happened.

What could be causing this?

Edit:
I relighted the pilot on Sunday morning and monitored it throughout the day. The last time the hot water was used was at around 8PM on Sunday and it was still working properly.

This morning (Monday) the pilot was out again and I relighted it.

Edit 2:
Tonight, I checked the pilot and it was still lit. However, after 2 people took showers at the same time (which probably cause the burner to kick in), the pilot went out. I am not sure whether it went out when the burner was trying to light up or when the burner turned off. After relighting the pilot again, the burner started up.