For some reason updatets.py is not successfully removing obsolete translations. This is a long standing issue. The workaround is to manually remove them from the .ts file. ref: https://forum.freecadweb.org/viewtopic.php?f=21&t=51825&p=483474#p482519 crowdin: https://crowdin.com/translate/freecad/7254/en-pl?filter=basic&value=0#6572886