I am not sure how prevalent this is, how to prove it, or if it is happening to anyone else. I assumed that I was seeing all of chat and may have just missed the occasional message that lead to awkward entrances/exits from conversations or had no effect. However, a couple days ago I was in chat while someone was telling a story (maybe 13-16 people in chat) and the story made absolutely no sense. I was asking for people to fill me in on the details and I was still getting random responses missing to the point where I had to leave the chat.
I am not sure how to replicate, test, figure out the issue, or even know if I had experienced it before (as I may not have noticed the missing messages before).
My computer was Windows 7, browser Google Chrome.
Maybe if a couple others can verify that they have experienced this problem then it will add some credibility to it.
PS: I was going to post this in the issues app under chat, but there was some sort of database error and it wouldn't let me at the time.