Idk if this has been found yet, but I was creating a modpack with Origins in it for me and my friends to play, and most of them don't have great computers so I wanted to use Sodium, Lithium, and Dashloader. The thing is Dashloader breaks when I use the default version of Sodium (an issue I will also be submitting a report for on their Github) so I used the Iris version that had Sodium packaged in it, and it works fine. Up until I added Origins. I whittled down the problem to The Iris version, and Origins. Fabric API and Not Enough Crashes are in there just to a. run the actual mod, and b. improve the readability of the error.

The error line reads as such:
Catching java.lang.ClassNotFoundException: org/spongepowered/asm/synthetic/args/Args$3

Not even sure what that even means but look for that line when looking at the paste bin: https://pastebin.com/9bsZ9Pqx

For context, I loaded the game, opened a world, placed and broke a furnace (which is what caused the crash when I had more mods installed, not sure why, but without it's fine), and exited the game. I will also report this same bug to Iris, with the same pastebin, bc I'm not sure which side is to blame for this crash.

P.S: This does not happen with just Sodium, all by itself so I have to think it's an Iris Issue.