New disk pads glazing during bed-in procedure

My bike is equipped with Sram Force Etap AXS and I’ve been using some BBB pads for quite a while. My bike shop recommended these, stating that they were compatible (and yes, they worked pretty well).

Now I need to change my pads. I’ve had some spares from the Swiss Stop brand for a while. I understand that this brand is quite good. Earlier this year, I purchased the model Disc 26 E because it’s for Avid Elixir/Sram XX (same as my BBB pads). But since the purchase, they have released the Disc 35 E which are designed specifically for my brakes and I intend to purchase these in the future.

I’ve been trying to set-up the Swiss Stop Disc 26 E for a couple days now. But I have some noise problems which I didn’t have with the BBB pads.
I set up the pads while being careful not to contaminate them, and I cleaned the discs using isopropanol. After following the bed-in procedure from sram (brake 20x from 15-20 km/h to walking speed, then brake 10x from 30km/h to walking speed), I noticed that the brakes were squeaking a lot.

After unmounting the pads, I saw this:

The scratch in the middle appears to be glazing because it’s very shiny. I’m a bit surprised because I’ve heated my BBB pads a lot more and didn’t observe any glazing.
I then sanded the pads to recover their original green-ish color.

I tried new bed-in procedures/sanding several times with the same results.

Does anyone has ever observed anything like that? Any tip how to fix this?

Thanks a lot!