devtrackers.gg
To the actual question: for some bundles, it seems like when you buy all purchaseable items from a bundle separately you can no longer buy the bundle itself. I had that with the lunar new year heavy blade skin. Doesn't extend to deluxe skin bundles though (thankfully) (not really thankfully, please DE rework that system, I don't want to pay 225p extra just for the syandana and weapon skins)
no promises, but we're taking a look to see how it might be tweaked for better flexibility