I am running Stardew Valley on my Mac. I am not able to donate any items to the museum in any of the slots under my inventory bar. They are still outlined in red like usual, but when I click on them with the item I want to donate, it's as if there's no slot there. I have been avoiding this by just using the tables that are located above my inventory, but I have just filled them up and am out of ideas. Has anyone else had this problem?
This seems to be a rather widespread known bug. Anecdotally speaking, I've encountered this on my Switch as well.
The solution appears to be to scroll to the spot you want to place the item before you select your donation, select which item you want to donate, and don't scroll the screen as you place your donation.