for some reason it makes the rocket stack size of some early items insanely high (2k) and completely ruins things like autosending resources to rockets.

If this is the only mod you're using then I can take a look otherwise I don't think there's any code in this mod that affects stack size of items.

I have the same problem, for example it makes fast inserters go from 50 to 450 rocket capacity, it affects all inserters except bulk and stack.
Yellow transport belts go from 100 to 2000 rocket capacity etc

mods: Space Age, Quality, Elevated Rails and Stable Foundations

screenshots: https://i.gyazo.com/5e84de6a185b75f5b792f3f5723e0650.png and https://i.gyazo.com/6babdd2a573a4da11bad1506776e98ca.png

Accidentally posted twice

Should be fixed in 1.2

The update fixed it for me, thank you!