I have the following formula in one of my Google Sheets which has worked for years.

=iferror(filter('Flag Duplicates 1'!A2:N,not(isblank('Flag Duplicates 1'!A2:A)),'Flag Duplicates 1'!Q2:Q<>"Duplicate",'Flag Duplicates 1'!O2:O=P1),"")

Suddenly today the Q2:Q<>"Duplicate" is generating an error and causing the filter to generate an “N/A” error (no records found).

Has Google changed anything recently? I use this approach to eliminate duplicates in many of my sheets.

The filter works if I take out the <> section and I have not been able to find a reference to this issue online.