Spelling & correction

a problem with Scrivener: sometimes (randomly) when writing a text, spelling and autocorrection stop working (also the automatic substitution of " into « for dialogues). On the other hand, if I go into fullscreen mode, they work.
Is it a known bug?

Many thanks

This is a known problem affecting some users … see https://forum.literatureandlatte.com/t/in-line-spell-check-not-working-on-some-projects/20113/1
for some discussion.

Mr X