Books still have an NBT tag (RepairCost of 0) after removal of enchantments using Grindstone

After using a Grindstone to remove an unwanted enchantment from a book and get some experience back, I noticed that the plain book left behind wouldn't stack with my other books in my chest. I then noticed that it still had an NBT tag, shown in screenshot 1.

Looking in my inventory using NBTExplorer showed that this tag is a RepairCost value of 0.

Further testing in creative had the same thing happen every time, also revealing that the NBT-tagged books stack with each other, but not regular crafted books (which is expected since the minecraft:book item can stack).

Simply having the grindstone remove this tag as well if a book is used should be simple enough with no negative effects, since the RepairCost tag is useless on a regular unenchanted book. These de-enchanted books can be re-enchanted without issue, so the issue is mainly with item stacking.

This issue wasn't present before Pre-Release 3 because enchanted books weren't able to be de-enchanted with a grindstone due to a now-fixed bug.