It seems that when mods add alternate recipes for space age sciences their researches can get grabbed as prerequisites.
That might be hard to explain but if you install this mod and Cubium (https://mods.factorio.com/mod/cubium) you can see that a lot of the researches got gated behind cube-mastery-4 because it adds alternate recipes for science packs.
Though there are some odd exceptions that make me second guess that assumption since it only grabs sciences that have metallurgic, electromagnetic, or argicultural sciences as ingredients. Stuff that takes Cryogenic is fine?

Heads up if you start trying to work on this right after I post this, there's currently a bug with that mod where it can't load on the latest experimental factorio version. https://github.com/ZacharyDK/Cubium/issues/27

Cubium got fixed so I experimented with this some more. Ended up fixing it myself by just hard coding the offending research as unreachable in the pack_production_reachability file.
That's an alternate solution, just giving users a list we could populate with tech's we don't want in consideration for being pre reqs.

thanks, im releasing an update today that hopefully fixes this ina way that works for you, but ill consider other fxes in the next update, and this override list idea too... let me know if you have any other suggestions

let me know if the fix didnt work for you, hopefully we're workin

It has somewhat worked, only cubium isn't changing the ordering of recipes which is good. But looks like now most of the techs are being put with recycling as the prereq instead of what I would assume should be the science unlocking the space age science.
This is just base game space age now btw.
I assume the recycling recipes for the science packs that just give themselves back are being factored in as the 'main' way to get the science packs? That's just off the dome, not from looking at the code yet.

That seems to be the case, added a filter on the "production_routes" function in "pack_production_reachability" to skip recipes with a recycling source class and things now depend on production science and the space age science.
Theoretically with certain mods the intended way to get a recipe could be through recycling but I don't actually know of any that do that.

That seems to be the case, added a filter on the "production_routes" function in "pack_production_reachability" to skip recipes with a recycling source class locally and things now depend on production science and the space age science.
Theoretically with certain mods the intended way to get a recipe could be through recycling but I don't actually know of any that do that.

Oops, sent that twice. Still unused to using the forums

thanks ill have to take a closer and longer look at it, im very new to this, ill keep you posted, thanks again