So I've encountered an odd few crashes, and I'm not sure who's mod is at fault here, I suspect some kind of incompatibility with each-other.
So, I get a crash related to Emendatus's included Hammer item, saying it's not present. But removing ExtReactors fixed that, but also showed another crash, that was fixed by removing ZeroCore, along with a succesful start. Updating Forge (43.2.4 > 43.2.6) didn't do anything to fix either crashes. This was after I went ahead and updated most of my older things. Even weirder, downgrading both of your mods don't fix the issue.
Crash with ExtReactors: latest.log crash log
Crash without ExtReactors: latest.log crash log
All other mods I updated along with ZCore and ExtReactors, if it helps:
XNet
Waystones
Supplementaries
RFTBase
Quark
Moonlib
Immersive Engineering
Cooking for blockheads
Botania
Balm

I do not know what the issue is but rolling back ExtremeReactors2 to the 1.19.2-2.0.60 and ZCore to 1.19.2-2.1.30 fixed it for me. could be a temp solution until ZeroNoRyouki or Zcore fix it?

I crashed as well, but I dont have Emendatus in my pack
crash-2023-03-01_22.06.47-fml.txt

Yeah rollback to ZC .30 and ER .60 for now, I'm checking what's going on

For some reason, when I build ZC last night on my main dev box, the jar was not obfuscated. I just pushed out ZC 2.1.32 and ER 2.0.62 to fix this. Please upate.

Have fun
Z

Thank you Zero! Have a nice day

upgrading to ZC 2.1.32 and ER 2.0.62 fix this for me thanks for the fast response Zero!