Anytime something that all of a sudden happens, my first go to is either this or within the program in question (the joys of rolling release OS and/or programs nowadays). Then see if anything got wonky within the file system. Got corrupted etc. Testing known good with new versions (as was mentioned) is also worth doing.
Flexi is flaky. It's kind of like it corrupts its own memory. Call support and they'll tell you to clear preferences do that and then you lose all your production manager profiles. I just had a problem where there was green tint on the illustration someone sent to me. It showed nowhere but in Flexi. OK, fine. I'll just make believe I don't see it. I restart my computer the next day and wham!!! No tint. Weirdest program (except for Windows) that I've ever worked with.
