Edit: Whoops other folks are reporting the same "issue", so it seems I am not alone.

I ran into a really weird issue with this credit... a United TravelBank purchase triggered it.

In early December I made a $102 purchase on AmexTravel and shortly afterwards received a corresponding credit. When the new year rolled around I made $200 in UA TravelBank purchases (obviously directly through UA). I received the full standard $200 Airline Fee credit and the remainder of the one-time $200 COVID AmexTravel was also credited to me at $98.

https://www.flyertalk.com/forum/32961533-post859.html

I had originally posted about this in the UA thread back in January because I was perplexed as to why I had received the $98 on top of the $200. I didn't make the UA purchases through AmexTravel, so it didn't even occur to me that it might have triggered that but at the very least the math adds up.

In February I made another AmexTravel purchase and I had been expecting the $98 to post for that. I asked in chat about that and the CSR referred me back to the United purchase... at the end of the day I am whole (I have received my $200 credit one way or the other) but it is bizarre to me that the TravelBank purchase tripped this.