I've only been able to test this with iron shovels, but tool durability seems to have been slightly altered. When the tool gets to 0 durability, it immediately breaks. In previous versions, you'd be able to get an additional use out of the tool at 0 durability. Now, it seems that 1 is the minimum durability.
https://minecraft.gamepedia.com/Shovel
The Official Minecraft Wiki states that an iron shovel has 251 uses, but that would be 0-250, not 1-250. Considering I have seen nothing about durability changing in the update notes, I can only assume it was altered accidentally.
See MC-120664