Unlike other similar buffs such as Angler's Instincts, additional player bonus and Artaeum Pickled Fish Bowl, this new companion perk can't be undone or avoided once you've permanently unlocked it. I think we need clarification from the developers on how these buffs affect things that are neither standard fish nor rare fish. That includes Leads, Furniture and Containers such as Pyandonean Bottles, Waterlogged Psijic Satchels and even the incredibly worthless Wet Gunny Sacks (that last one could honestly use some improvements). What we know for sure is that these buffs increase the drop chance of rare fish but what it doesn't say is which drop chances of other items are being decreased to make this possible. If it's just the drop chance of standard fish, we don't have a problem. But if this also decreases the drop chance of non-fish items, that's another matter entirely.
If the latter is the case, I can imagine a few possible solutions:
1. Change it so that these drop chances are no longer diminished by these effects or have it even improve them
2. Give us the ability to toggle off the perk items we receive after gaining the associated achievement for that companion
I suppose option 2 is probably a good idea regardless of how these drop chances work.