It was working completely fine 2 hours prior, but now windows defender is marking it as a trojan and aggressively deleting it. I've downloaded the file through prismMC and directly from curseforge it didn't make a difference.

ars_nouveau-1.20.1-forge-1.4.9.jar

This can happen from time to time with mods and is typically out of our control beyond reporting the file to Microsoft.