Collections (requesting mod response)
Once an item is in your collection (as in it’s lit up on the collection menu) you don’t need to hold onto it.
A lot of collections are intended to be long-term goals and/or things you complete gradually while playing (Trash Collector and the ones for collecting armor and weapon skins for example). It would be extremely impractical if you had to hold onto the items until you have all of them.
Edit: If you’re really going to insist on a mod response you’re going to be waiting over 24 hours at absolute minimum because it’s 8:40am on Sunday morning where they are, so no one will even look at this until tomorrow morning. You should also be aware that they very rarely answer questions like this and are even less likely to answer ones that demand that they do.
“Life’s a journey, not a destination.”