Hello!
The forge version uses the fabric method for light "getLightEmission()" instead of "getLightEmission(blockState, level, pos)"
This causes for example in Supplementaries: lit candles on skulls don't emit light.

I don't think this is "forge vs fabric methods" as much as it is "vanilla vs forge-added methods"

MehVahdJukaar/Supplementaries@e796313 resolves the specific conflict here, but technically I should use the hook anyways.

Yep the Supplementaries Dev said I should still report the issue as other Devs may use it. Thanks for looking into it !
Any news on Create compatibility ? On 1.18 it still crashes with starlight

36a1c6c