The bug
Dropped items do not render behind transparent blocks. This is not the case for dropped blocks (such as stone for example), however transparent blocks are affected as well (see MC-165156).
Linked issues
is duplicated by 10
MC-165532
Items with no 3D model are invisible through the water's surface
Resolved
MC-165364
Food items and slime and honey blocks can not be seen under water
Resolved
MC-165535
Flat items no longer render behind transparent textures
Resolved
MC-165564
Items Do Not Render Behind Glass, And Sometimes Water
Resolved
MC-165591
Items do not render in water
Resolved
5 more links
Fixed in 1.15 pre-1.