It doesn't look like the custom name component is being set on tipped arrows, meaning all tipped arrows with Polymer potions are called "Uncraftable Tipped Arrow".

Everything works fine on regular/splash/lingering potions.

I am experiencing this same issue, but also with regular potion types. This is likely due to the changes to how the item name component works on "custom naming" items

I also have found that lodestone compasses have the same issue
Priority change: https://minecraft.wiki/w/Data_component_format#:~:text=The%20name%20provided%20by%20the%20item_name%20component%20now%20always%20has%20the%20lowest%20priority.

The potion name should be defined in the potion_contents component in instead of the item_name