Hello,
I'm using the Soul Spawner and the Mob Farm but everytime I try to use them It "clear" my inventory, to recover my own inventory I have to open a chest for example.
I think It's an issue from the inventory of the block interfering with mine.
Another thing is I can't use hopper on the mob farm and the spawner don't seem to work.

Here are some screenshots :

Before opening

Opening

After opening

After opening a chest, everything reappear

Restarting the server and my shaders worked.