I just started using the beta regularly. I am working on a fantasy novel. As a result, there are a variety of words i need to add to the dictionary. I do this by running a spellcheck and once the word f found, I add it to the dictionary.
I have noticed that the word and any following punctuation is highlighted by the spell check and, as consequence, the work AND the following punctuation is added to the dictionary. I noticed it happens when the new word is at the end of the sentence but it happens with commas as well.
I am running a Windows 10 system.