From @aerych:

I pull to refresh, refresh finishes and I see a prompt that I have 20 new posts. Tap the prompt. The first post visible in the list is 7 days old. Pull to refresh again, when it refreshes the newest post is 4 days old. Rinse/ repeat, now its 1 day old. Pull to refresh one final time and I get 17 results (hey I reached the end of the list) and the most recent item is 22min.

This only happens when FP hasn't been refreshed for several days. Most likely caused by this code which loads newer posts based on timestamp, which shouldn't apply to FP.