The bug

dripstone_thickness is an accepted block state for copper blocks, and copper_oxidation is an accepted block state for pointed dripstone.

How to reproduce

1. /setblock ~ ~ ~ dirt["dripstone_thickness":"base"]
→ It errors since that state is inapplicable
2. /setblock ~ ~ ~ copper_block["dripstone_thickness":"base"]
→ Not only does it not error, it places an oxidized copper block