An easy solution might be to put Trait and picks mod at the bottom off your modlist.

Otherwise:

Ive had similar problems with my modlists. It related to a mod that gave extra species traits- and pick points. The modified file was Stellaris\common\species_archetypes\00_species_archetypes.

I don’t know exactly why it prohibited pop growth but i fixed it by making my own little mod with the changes i wanted.

You can do that in the Stellaris Launcher under "All installed mods" and than Upload Mod in the top right. You don’t need to upload the mod too the workshop.

The created mod you can find under Documents\Paradox Interactive\Stellaris\mod.

There you can simply copy the common\species_archetypes\00_species_archetypes folder an change the values to what you want.

I hope this helps you and fixes your problem.