Mined block drops turn grey for a short amount of time

I started a new survival world in the snapshot and silly me, I was spamming shift when I was punching down a tree. Then I noticed that when I broke the block, the drop was grey for a very short amount of time. So then I further tested while just holding shift. Then I tried just breaking a block without holding shift and it still did it. I hope this bug can be fixed because it is annoying. Also, it seems from what I have tested, it only does this with Spruce Wood (That's the tree I punched down) and dirt. It does not do this with sand.