I have a strange thing happening - dwellers I send to explore wasteland are automatically returning to vault after finding a little amount of items (4 or 5).
The exploration log says: "That's as much as I can carry. I better head back and show the Overseer what I found".
Before today they successfully carried up to 30 items and never returned to vault on their own.
I don't know is it relevant or not, but I have a lot of free storage space available.
What caused this change? What can I do to prevent this?