While trying to add JER as an optional dependency with the following lines in my build.gradle:

    maven {
        name = "bintray-way2muchnoise"
        url  "https://dl.bintray.com/way2muchnoise/dev/"
    }
...
    compileOnly "jeresources:JustEnoughResources-1.12.2:0.8.+"

The jar gradle gets is deobfuscated, despite not targeting the deobf jar. This causes errors with mismatched MCP mappings and may probably be unintended.

Not supporting 1.12 anymore, please reopen the ticket if this is still an issue.