For meta items:
The tooltip name of a meta item doesn't get cleared correctly if that slot gets replaced by another meta item. You don't need to directly swap it, just moving a new meta item around to a slot that used to have a meta item reproduces this issue too.
https://youtu.be/onfpztbRAvM
For hotbar:
Similar issue but only happens when you replace an used slot with another block. If you highlight/select that block to build with it, the tooltip name refreshes and it fixes itself.
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not fixed
Slots will retain previous meta item names when a new item is placed in the slot, this also happens for creative mode items.
https://youtu.be/LaiB5HPMH1g