Ohuna Companion Issue

Hey guys, working on my Taivan meta achiev and I only have one ohuna companion color left from grand hunts to finish the achievement. I’ve done far too many attempts (20+ purple boxes) on this last companion color and am starting to get worried.

My question is: if the companion color dropped on an alt, would it be able to drop again on a different character if you didn’t learn the appearance? Has anyone else had an issue with a distressingly low drop rate on their last color?

I assume that the loot rules are based on your indexed collections, as opposed to if an alt has the unlearned item in their bag, but I just want to make sure. Am I really just unlucky?