I have been having the same problem with QBO automatically pulling transactions from BoA since early March. I used to also be able to upload a QBO file downloaded from BoA; that has also ceased to work.

I happened to have an old QBO file from September, 2019 and compared it to the more recent ones. The only difference is that now, for each transaction, BoA is inserting additional fields, like this:

<MERCHCAT>

<EXPCAT>
 <CARDNUM>
 <CARDNAME>
 <MCC>

I removed those fields manually from the QBO file using Notepad, saved it, uploaded it, and VOILA ...joy

Now to figure out how to get BoA to stop including those fields at the source.

In the meantime I'm using the 'findstr' command from a command prompt window and it removes all the offending lines from a QBO file in one fell swoop; Then just upload the modified file, "stmt1.qbo" instead - yeeha :)

findstr /v /i /c:"<MERCHCAT>" /c:"<EXPCAT>" /c:"<CARDNUM>" /c:"<CARDNAME>" /c:"<MCC>" stmt.qbo >stmt1.qbo

Plug that line into a batch file, keep it in the same folder as the bad QBO file, and just double click the batch file to avoid the futile QBO and BoA support $hit $how