Shulker disappear

[deREALshocK]

Today i put my Shulker in the Crafting Table and as soon as i pressed ESC for leaving the crafting table, my shulker was gone. im pretty sure this is cause Stackableitems cause i dont have any other Plugin on my server and i already noticed in the past that some items was gone/duplicated while doing some fast things/moving in the inventory. anyway i think this bug is not reproducible. it happens random i think but still want to report this cause it was and important shulker.