For me VAT address field disappears and VAT payment is asked every time I select any address other than main.
Yes, address choice seems to be connected to the bug. VAT number is clearly visible, I make sure everything's OK, choose the address, the VAT number disappears from the screen but I think it
has to be a display bug, and click "order". Lo and behold, the VAT number
actually disappeared from the order, not just a display bug!
I have reported this issue to no avail.
Changing primary address sets it in "pending" state for a week, after that someone contacted me and asked why I want to change my address. No shit Sherlock, I have moved!
This totally kills my business with Digikey because I work at two different locations and want parts shipped to these alternate locations which is why the whole possibility of entering address (or choosing between presets) exists. But because of the VAT number bug, I just buy from Mouser. They can deal with business VAT ID like any sensible company.