Hello there @TheBestTomo!
A very similar scenario took place in the another thread, as reference:
At that moment, the problem was caused by an issue from the engine itself, and it was promptly fixed. There’s currently no reports of any FAB related issue, thus the best course of action at this point would be to reinstall the engine, which will restore the missing FAB plugin.
After the reinstall is complete, refresh your FAB folder, and your items should be restored.