principum tps low ?
principium not going well, rendering takes a long time, long delays , spikes aso ...
This might be your problem
Had problems like that when I started but monkeybug34 tipped me of 2 use the Curse Launcher instead and it disappeard all together.
At the time the server started 2 act up monkeybug34 and Ovraline also was online. It first crashed and then afterwards was totally bonkers. They stopped playing but I stayed on for a while longer but it didnt go away.