Here is what I have seen on the FB group and hear for it burning up.
Hot:
- Battery charging on and powered from a 13V source (not the wall cube). It will charge but it will get to about 50C and things fail
- I don't think the ATU can handle high antenna SWR values and run 10 watts from the radio. I have seen a few 20m coils fried from various people. This seems consistent with your 20M operating.
What antenna were you using?