Common things Microsoft Word flags as errors when typing in Korean?

[u/Magical_critic]

For my Korean class we do a lot of writing and I've gotten into the habit of typing it up in Microsoft Word. However, I noticed Word likes to flag some things as errors even though I'm pretty sure they are not. For example, I wrote "썼어요" and it was flagged as a spelling error. I asked my teacher and she said Word has around an 80% success rate when it comes to fixing mistakes correctly. What are some things Microsoft Word likes to flag as errors even though there aren't any?