Caused by: org.spongepowered.asm.mixin.injection.throwables.InvalidInjectionException: Invalid descriptor on seedcracker.mixins.json:ClientPlayNetworkHandlerMixin->@Inject::onInit(Lnet/minecraft/class_310;Lnet/minecraft/class_437;Lnet/minecraft/class_2535;Lcom/mojang/authlib/GameProfile;Lorg/spongepowered/asm/mixin/injection/callback/CallbackInfo;)V from mod seedcracker!
Like you mentioned, Mojang has already patched it, which means that it's patched on Aristois. In addition we've updated to fabric loader v0.12.9 which has also patched it before Mojang did.
It's not an Aristois issue, it's because 1.18 is pushing the 2G RAM limit. If you check your f3 menu I would bet that it's around 80-95% usage. Allocate more ram and it will be fixed.
The log you sent isn't even from 1.18, if it's a different issue then please make a new support post.