In version 0.25.2 (and seen in some prior versions) running on Pop!_OS 20.10, I've had issues with corrected words reverting when attempting to correct them. When right-clicking on a misspelled word and selecting a replacement, it will briefly change the word, and sometimes immediately revert back to the incorrect version. This does not happen on every word. It will sometimes happen only once on a word, but can sometimes happen repeatedly on the same word.