Re-reported version of MC-167972 as requested.
The bug
If an item is sufficiently damaged so that its remaining durability is a negative number, the durability bar can become incredibly long in the negative direction depending on damage level.
How to reproduce
Execute the following command:
/give @s golden_pickaxe{Damage:2147483647}
Observe
Expected results
No idea what I was expecting with this one. Prior to 1.15, it'd display as empty. In Alpha, it would refill in the normal direction as solid red.
Actual results
Comically long durability bar.
Linked issues
duplicates 1
Attachments
Comments 1

This is MC-259587.