https://github.com/RCXcrafter/EmbersRekindled/blob/rekindled/src/main/java/com/rekindled/embers/blockentity/FluidPipeBlockEntityBase.java#L291

A bunch of the blocks got broadcast mechanics. This causes a lot of network lag on servers. These messages should only be sent to closeby players

Yeah this was brought to my attention a few days ago, I'm currently working on fixing it.

On that note, why are you not using normal blockentity client sync for this?

It should be good now in version 1.3.2