Subreddit switching sometimes doesn't work properly

**Describe the bug**
Switching subreddits doesn't work if the current subreddit isn't fully loaded

**To Reproduce**
Steps to reproduce the behavior:
Open a subreddit with a lot of media posts and then quickly switch to another sub

**Expected behavior**
The posts that are being loaded for the current sub should all be deleted and repopulated with the new selected subreddit post.
