Dalek Mod Version: Update 63
Location of bug [E.g. Servers]:Poppins' Umbrella
Description: Poppins' Umbrella, if held in the offhand, can write the "open" tag to items in the mainhand. This can lead to miscellaneous items in your inventory being unable to stack with others. I assume this bug happens because the umbrella only ever expects to be toggled when in the mainhand, and therefore never checks to see which hand it really occupies, so it just writes the "open" tag to the mainhand, even though that item isn't the umbrella.