Entities Going Invisible

So I’ll kind of just make this short and sweet. On my Pixelmon server, we’re having a problem where if you unload a chunk with entities in it (players, NPC, pokemon staties, holograms, etc.) and enter that chunk again, those entities just disappear. I’ve only noticed a fix to be teleporting away and back into that said chunk. One way I’ve been kind of getting around it is just vanishing and unvanishing. This makes me think its a problem with vanish and then maybe a problem with Nucleus. Someone please help because I’m really wanting to open my server up to people soon and this problem would make it beyond annoying and inconvenient.