Passolo blocks file on entire system

I have a fairly large project consisting of non-standard text-based files for which I wrote a parser. This has worked well for 2 years. But since a few weeks one file that doesn't seem to be different to the others causes problems. If I preview the file in the text parser rule definition dialog BEFORE I add it to the project, everything seems fine. (see screenshot)

As soon as I add the file to the project, the file suddenly shows no translatable strings and Passolo also blocks the file on the entire system (i.e. it can't be renamed, changed, overwritten in ANY application). This can only be rectified by completely closing Passolo (not just the relevant project).

Anything I can do?