Sea Pickles randomly break in my aquarium.

My Aquarium tanks are either 4x2x3 internally or 2x2x3 internally. The larger ones sit on the ground with the smaller ones above them. Pickles break when placed in the top tanks (I.e the smaller ones). Therefore; This only seems to happen if they are placed on a block which is directly above water or within this smaller space.

I have included a screenshot which recreates the phenomenon. Non flowing water beneath a solid block with pickles on.