Minecraft has crashed!
net.fabricmc.loader.impl.FormattedException: java.lang.RuntimeException: Mixin transformation of net.minecraft.class_310 failed
at net.fabricmc.loader.impl.game.minecraft.MinecraftGameProvider.launch(MinecraftGameProvider.java:418)
at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:77)
at net.fabricmc.loader.impl.launch.knot.KnotClient.main(KnotClient.java:23)
Caused by: java.lang.RuntimeException: Mixin transformation of net.minecraft.class_310 failed
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:252)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.tryLoadClass(KnotClassDelegate.java:150)
at net.fabricmc.loader.impl.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:155)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
at vazkii.patchouli.client.handler.BookCrashHandler.appendToCrashReport(BookCrashHandler.java:23)
at net.minecraft.class_6396.handler$glo000$patchouli_addContext(class_6396.java:1016)
at net.minecraft.class_6396.(class_6396.java:57)
at net.minecraft.class_128.(class_128.java:32)
at net.minecraft.class_128.method_24305(class_128.java:272)
at net.minecraft.client.main.Main.main(Main.java:153)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at net.fabricmc.loader.impl.game.minecraft.MinecraftGameProvider.launch(MinecraftGameProvider.java:416)
... 2 more
Caused by: org.spongepowered.asm.mixin.transformer.throwables.MixinTransformerError: An unexpected critical error was encountered
at org.spongepowered.asm.mixin.transformer.MixinProcessor.applyMixins(MixinProcessor.java:392)
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClass(MixinTransformer.java:234)
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClassBytes(MixinTransformer.java:202)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:247)
... 16 more
Caused by: org.spongepowered.asm.mixin.injection.throwables.InjectionError: Critical injection failure: Redirector checkForEntity(Lnet/minecraft/class_636;Lnet/minecraft/class_2338;Lnet/minecraft/class_2350;)Z in sentimentality3.mixins.json:GrassSwingFix from mod sentimentality3 failed injection check, (0/1) succeeded. Scanned 1 target(s). Using refmap sentimentality3-refmap.json
at org.spongepowered.asm.mixin.injection.struct.InjectionInfo.postInject(InjectionInfo.java:468)
at org.spongepowered.asm.mixin.transformer.MixinTargetContext.applyInjections(MixinTargetContext.java:1385)
at org.spongepowered.asm.mixin.transformer.MixinApplicatorStandard.applyInjections(MixinApplicatorStandard.java:1052)
at org.spongepowered.asm.mixin.transformer.MixinApplicatorStandard.applyMixin(MixinApplicatorStandard.java:400)
at org.spongepowered.asm.mixin.transformer.MixinApplicatorStandard.apply(MixinApplicatorStandard.java:325)
at org.spongepowered.asm.mixin.transformer.TargetClassContext.apply(TargetClassContext.java:421)
at org.spongepowered.asm.mixin.transformer.TargetClassContext.applyMixins(TargetClassContext.java:403)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.applyMixins(MixinProcessor.java:363)
... 19 more

Does that modpack have anything that touches grass?

maybe, im not too sure.