Dropped items won't float up near bedrock

I was digging chunk to chunk in the ocean, clearing  everything out of ticking area for mob grinder.  After the aquatic phase 2 update, digging Y:10 layer, where magma blocks are common found, causes dropped items to either floating up or fall onto the ground.  At Y:9 and below, all dropped items will fall onto the ground instead of floating up to the water surface.