The Bug

In 1.15, If the durability of the item is lower than 0 (negative number), the condition on the picture will be displayed

In 1.14.4, items below 0 durability will show the same durability bar as 0 durability

How to Reproduce

Give yourself an item with negative durability, e.g.

/give @s minecraft:golden_axe{Damage: 114548}