As soon as I enable this mod on an existing save, I start seeing additional products in my scrap recycling feedback loops, even without any recipes unlocked.

This is not really an issue, however the belts become flooded with fish. This looks to be the Microplastic Filtering recipe in reverse, which gives an extreme amount of fish back for each piece of plastic

P.S. Great mod idea, have you considered integrating with Vanilla Galore/Space Age Galore?

Oh interesting. I haven't unlocked recycling yet so I can't debug it yet. I assumed (hoped) that recyclers would need me to explicitly set the products of recycling, but I guess the devs made it dynamically scan all added recipes, which is a great idea, makes it very flexible and open to other mods, but in this particular instance is kind of a problem. Hmm. I'll see if I can make a recipe not get added to the recycler or something. I'll post here if I fix it or if I figure out that it cannot be fixed, either way.

I have never heard of that mod, but I'll check it out :)

Yeah they are auto-generated in the Quality mod. There are a couple of recipe.category's which are excluded (smelting/chemistry) but there is also a more general check for recipes to be excluded (in prototypes.recycling):

    -- Allow recipes to opt-out
    if recipe.auto_recycle == false then return end

Okay, so all I have to do is set that flag to false for each of my recipes, and none of them will interfere with recycling? Thank you for that, by the way.

I think it's fixed now. Please let me know either way. I could not reproduce the issue myself so I'm kinda flying blind.