ghost liquids

[zakwanasim]

this is a very well known bug with lava or water not being updated to the client even though the liquid isn't there server side, if u continously place lava and pick it up at times it starts teleporting around the map or just stays in the 1x1 block for the client

[iamnoksio]

by improving (liquid, block) placement & interaction you should achieve to do it yourself

[anzz1]

This is something that is presumably fixed by this plugin : https://github.com/ThatApplePieGuy/PacketPatcher/
However the fix should be ported to the server core and the other fixes from the plugin too