For myself and my SO, almost everything. My feeds don't load until I refresh them 3/4x, comments disappear and reappear randomly, voting is a shot in the dark. It's made Lemmy pretty much useless for me. It seems like every other day or so it randomly signs me out, and it's a crap shoot as to whether I can sign back in without reinstalling.

SO can't comment, period. He's uninstalled/reinstalled, cleared cache, logged in and out a thousand times... Jerboa just will not let him comment. He also cannot load any feeds unless Jerboa feels like it. Overall a miserable experience.

I've had zero issues with Sync so far 🤷‍♀️