Latest Figma update broke all my Font styles

Updated to latest FIGMA version today, and now all my font styles have been detached from every single artboard?
Its a HUGE project and now I have to manually go and reattach everything?
It even changes some stylings of fonts from Regular to Bold?

I haven’t started using variables yet, so its still pre-Config 2023 - has anyone else encountered this with the new update? am I going mad?

I haven’t experienced this exact problem, but some of my text styles seem to be detaching themselves at random and it’s making me think I’ve gone crazy. I can’t figure out what’s causing it.