Blocks can't be placed or dropped when given from creative inventory using number button in the empty hotbar slot with the same number.
This occurs for every second block, that was given in the same hotbar slot as the previous one after it was deleted.
Steps to reproduce:
Open inventory in creative mode.
Choose any item or block and pick it in any hotbar slot using corresponding number button.
Delete given item or block by shift+clicking on it.
Give the same item in the same hotbar slot as in step 2, again using corresponding number button.
Experience the bug while you can't place given block or item in the world, in item frame or drop it.
If player opens inventory between steps 3 and 4, bug don't occur.
In step 3 if item or block was dropped instead of deleted, bug don't occur.
Item or block from step 4 disappears after reopening the world or picking any other item from the ground.
Related issues
Comments


Yes, I'm sure. I have rechecked it right now in 17w18b, it's still there.
Sounds really similar to MC-2912, are you sure you are playing in the snapshots of 1.12?