Lemmy-UI has always has its share of software gore. Haven't used it in forever, but good to know it's still there.
Back in the 0.17.x days and prior, it used websockets instead of the HTTP API. After a few minutes of browsing, the feed would just start rapidly flooding with every post ever made, and you'd have to refresh the whole webapp to make it stop. Repeat.
Oh, and it would also occasionally just send you the wrong session. You'd be browsing as yourself, refresh or click into a post, and you'd be someone else on the instance.
I've been using lemmy almost a year now and it has been fairly smooth. But I still get logged out every time I refresh some community pages which is strange.