This appears (for me at least) to be a consistent issue.
Trying to switch items on the ship (usually cannons but happens with flag) and the game just hard crashes almost every time. It's annoying when you've just found a really good Cannon in a shipwreck, crashes and when you reload you don't get the item this time around.
Its workable by saving anytime you want to change anything in case of a crash but damn it's annoying