Hey! Yeah, this is a caching issue that pops up sometimes. NetSuite stores ship-to addresses in multiple places and doesn't always sync them immediately.
Try clearing your browser cache first, then check if there's a default ship-to set on the vendor record that might be overriding the subsidiary one. Also worth looking at location records if you're using those since they can interfere too.
If it's still pulling the old address after that, you might need to do a hard refresh of the subsidiary record or check if there are any saved transactions using the old address as a template.