well, it made it to the issuelist https://unifaceinfo.com/fixes/issuelist/31863.php

Unfortunately, the bug has not been corrected with patch 003. Are we REALLY expected to open the SQL workbench and create a sqlstatement to find a signature with a given description and transfer the signature name into the Open Signature Form manually? BTW: using $IDF with the standard SQLITE database, the sqlstatement looks like select USPECNAM, UDESCR from USSPEC where UDESCR like 'base%'

Further investigations have shown that in 10.2 the open signature had 3 fields: component subsystem description as u10 doesn't have a "subsystem", in 10.3 the open has only 2 fields. BUT it looks like someone (instead of deleting the subsystem field) has reused the "subsystem" entry field (which was set UPC) now for the description, no tests done -> chaos delivered