I’ve noticed this too a while ago. Then they also had been removed from the buy catalogue at the fish shop. Have you been able to buy them or are they from the cheat?
showUserDevCategory [true/false]
Unlock all unpurchasable building items
* Note: Items unlocked using cheats are excluded from saved room and property presets.
I think they got removed from the fish shop because they are buggy but they forgot to delete them from devs category and the cheats.
Why? Instead of filling my inventory with 80 pieces of bait. it’s better to buy and use 5-6 pieces.
Fishing five times in a row was buggy too for many months, I guess the devs are too busy to fix the baits - or they forgot. Who knows 
There are so many other bugs around fishing that never got fixed or even acknowledged.
The inventory size is quite small. I have to buy a lot of single-fish bait to get my fishing skill to a level 10.Not being able to use this bait is costing me a lot of inventory weight.
I keep activating the “FeatherBag” cheat on my zois for that.
It’s even worse when you’re a farmer or a cook, and you have to carry all of these on your person.
the inventory system needs a lot of refining, but until then “FeatherBag” it is.
We can’t do anything to that bag. We carry it with us like an ornament.