The bug
Items with partially transparent textures, such as stained glass, stained glass panes, honey blocks or slime blocks, no longer let water render behind them. This happens both when holding them in the hand in third-person mode, and when those items are dropped.
Related issues
duplicates
Attachments
Comments


So do slime blocks. Isn't it supposed to be transparent?

I have added a screenshot. If you look closely at the water rendered behind the block in my hand, you can see that there is no water... Additionally, some sides of the block are more transparent than others depending on how your camera is angled.
(I have only noticed these issued while in third person)
Can confirm. Also happens with dropped items.

Isn't this basically the same as MC-161896? Doesn't really matter if you look at water or a nether portal through such items, same result ...
Yes. Merged into MC-161896.