Yesterday I found out that if you have a block which can be removed with the wrench and sticks with glue to another block (in my case bottom), you can dupe it by having the glue in your off-hand and then try to remove the block with your wrench. The result is the block in your inventory, but the block was never removed. It also only works on specific angles for some reason.

Video: https://youtu.be/2UHxO3WEKXg

This was addressed in 0.3e, feel free to re-open if its still an issue. Cheers~