Wild bait and magnet bait disappearing - whole stack in one cast

Hi - I am playing Stardew Valley on iOS (iPad). I have tried multiple times to use wild bait and magnet bait, and on most if not all occasions, have encountered problems with the bait disappearing after one cast. I have checked prior to casting to make sure that multiple pieces of the bait were on the rod. For example, it just happened again when I had the treasure tackle, and 15 pieces of magnet bait. One cast, and I received a message saying that I had used my last piece of bait. Sure enough, all the magnets were gone. Trying SO hard to find a Dino Egg - need to be able to use the magnet Please help. Any suggestions? Thank you in advance!

Edited to add: not using any mods.