One of the many Idiotic programmings of the game. I too have experienced this. On top of this you have duplicate Legendary DWELLERS and "rare" 500 cap cards in lunchboxes reoccurring so often it turns Bethesda into nothing short of liars. Their promise on paid lunchboxes guarantees at least 1 rare item in every lunchbox. 500 CAPS are not RARE!!! This leads one to only see the dishonesty behind the game and alas, falls into being nothing more than a cash grab app masquerading as a fun free introduction to FO4. This will fit right in with Bethesda's hints of paid mods for FO4. Love of money has destroyed what could have been a really fun experience with FS.
Lunchboxes are designed for newer players to have a boost in building their vault. I even thought 500 caps card was ok at the beginning because it was so hard to get any.