This is most likely the Kotlin compiler inserting default bridge code in your implementation, https://kotlinlang.org/docs/compiler-reference.html#jvm-default-mode
You can fix this by configuring the compiler options in your build.gradle.kts file.
I’m using this, but all isn’t in the latest list of options. You may have to change this.
kotlin {
compilerOptions {
freeCompilerArgs = listOf("-Xjvm-default=all")
}
}