When maps are put in an item frame and you walk about 10 blocks away, the map will fade until you can't see the map, only the item frame. If a group of maps are around each other, only one will fade.

What do I do to stop the maps from fading?

Try uninstalling any other mod you have installed. If it still happens with only ImmediatelyFast installed then upload the game log and steps to reproduce the issue

Ok, I'll the extra mods I added to the pack and see if they caused the problem.

I'm using the prominence 2 modpack. I don't have access to the game logs for the server I'm on. The issue happens whenever I go within 10 blocks of an item from with a map in it. Is there something else I can try before I try emailing the admin to ask about the logs?

ImmediatelyFast is not a serverside mod. I would only need the client log as thats the only side IF does anything on. Its very likely that another mod is causing the issue, so please test it with only ImmediatelyFast first (Or alternatively remove only ImmediatelyFast and check if the issue is fixed)