The spell checker is a bit too eager right now, and will spell check words before they’ve been completed. This is very distracting when working on documents. It should only kick in once the word has been completed with a terminal character at the end.
Hopefully defering evaluation is a quick fix 
I’m replying to a 13 year old post because I’m having the same issue. Any luck?
edit: also, spell check is flagging some (not all) words with apostrophes as misspelled – I’m, for example, or Bob’s. I just started evaluating Sublime yesterday. Other than the spell check issues I like it, but lack of proper spell check is a deal breaker.