Proguard creates these when obfuscating, but it throws an exception when you try to merge two mappings by the obf names:
java.lang.IllegalStateException: Duplicate key net.fabricmc.stitch.commands.tinyv2.TinyField@4623e502
at net.fabricmc.stitch.commands.tinyv2.TinyClass.mapFieldsByFirstNamespace(TinyClass.java:63)
at net.fabricmc.stitch.commands.tinyv2.CommandMergeTinyV2.mergeClasses(CommandMergeTinyV2.java:190)
at net.fabricmc.stitch.commands.tinyv2.CommandMergeTinyV2.lambda$merge$0(CommandMergeTinyV2.java:140)
at net.fabricmc.stitch.commands.tinyv2.CommandMergeTinyV2.map(CommandMergeTinyV2.java:304)
at net.fabricmc.stitch.commands.tinyv2.CommandMergeTinyV2.merge(CommandMergeTinyV2.java:134)
at net.fabricmc.stitch.commands.tinyv2.CommandMergeTinyV2.run(CommandMergeTinyV2.java:118)
Proguard creates these when obfuscating, but it throws an exception when you try to merge two mappings by the obf names: