I can’t find anything that says you can’t, but I can’t do it , is it a bug?
Lovely.You can't store anything that has the mission icon I have come to find out. .... the game will mark any vendor that has that with a symbol and if you buy the item with that symbol it cannot be stored on your FC.
I learned this the hard way trying to help along my alt account with unlocking the engineers and bought some Soontill relics - you can stock as many as you want (I bought 600Yes OP if you are the owner of the carrier, you can. See the [Transfer] button in the inventory tab.
Unfortunately, you cannot trade even small amounts of rares in the carrier's market.
I stored my Hutton Mug in mine. Worked fine.