To elaborate, I'll be roleplaying, and it'll be 5 minutes and I can't see any new posts. Then I'll type and post, and many posts of other members will appear. Is this a glitch?

Nope, that's simply how the site works. The site isn't live or anything, so you need to update/reload the page to see if anyone has posted. You can do this by switching pages, or clicking on the page number you're on, as reloading can create a double post.

The page will also refresh if you click on sales chat or the refresh button above sales chat

Okay, thanks for the help!