Alright, no songs are marked with (!).
The steps I took that caused the issue went in this order: Opened MusicBee, clicked my playlist (as when on mobile I saw my vocal only track had instrumental in it) attempted to delete 8 tracks through the extended art view and that's when I got the flashing error+CTD.
Any view that doesn't use album art seems to load quickly (in that specific playlist).
Seems like regardless of starting from the bottom or top of the playlist with adding songs, it still loads quite slowly. It starts to really lose speed around 5 rows (each row having 8 albums each). This problem consistently gets worse as songs are added.
I'm very happy we have an error log function, I completely spaced checking for that.
http://pastebin.com/BRg1125xThe pastebin has the first error of that timeframe, which I believe was what corrupted/messed up the playlist. All the other errors of that night involved my attempts to reproduce the problem, none had the same effect though. Although un-related, I was able to reproduce another error regarding the new extended view, but that's a different non-consequential thing.