Plugin problems and worlds not loading

It's been like this for months now and nothing's been fixed even though I've reached out on Discord. The worlds not loading problem which was mentioned in another bug report a few months ago is still happening. Certain areas of my map aren't loaded in correctly. Along with that, the head plugins are completely broken. The /head command itself works but saved toolbars with heads on them refuse to load. Sometimes when moving a head in your inventory to the main toolbar, the head disappears entirely stating I don't have permission to use the head. This problem happens with banners as well. The final thing I've found is that some entities seem to be broken as I can't place any painting or item frames and all existing ones in the world have been removed. It would be very appreciated if these problems could be fixed, as I've waited a long time for them and they make the game much harder to play.