Torch invisible under water

as the the title says i wanted too see what happends when you make water flow on to a torch it dissapeared but no block dropped so i thouht it is under there but when i wanted to place back the block i broke but i couldent here are some pics

here i show the light on the block it indicates i can place a block there but here i cant and i blocked sourceblock and look what we got here

Now the question is which one is the bug? That the torch doesn’t drop or that it’s invisible?^^

at start the torch burns under water still
later the dev`s correct it → torch dont burn more under water, but you can place it under water

the bug is that the torch is invisible

It seems so yes and I’d hope it is this way but it might as well be the other way around^^