Last version that worked for me with returned Result classes was 1.13.9. I've checked all the commits that were added between 1.13.1 and 1.13.10 and realized that this change was responsible for this behavior.

I've reverted changes, at it looks like all tests are passing (even those added in the below PR that was causing issues). I think the change is not needed anymore and can be simply reverted

However I tested it mostly with Result class, so alternatively I can change this PR to only include workaround for Result:

actual val <T : Any> T.boxedValue: Any?
    @Suppress("UNCHECKED_CAST")
    get() = if (!this::class.isValue_safe) {
        this
    } else {
        val klass = (this::class as KClass<T>)
        val boxedProperty = klass.boxedProperty.get(this)
        if (klass == Result::class) {
            boxedProperty
        } else {
            boxedProperty?.boxedValue
        }
    }

This PR fixes: #1351, #1338