Unexpected behaviour with latest version of kotlinCompilerExtensionVersion and Kotlin 1.6.0

I have a project that is using Jetpack compose. After I switched to the later version of kotlinCompilerExtensionVersion I had a problem: part of the composition wasn't drawn anymore. I found out that the problem was with a code similar to this one:

variable?.let {
    ComposableFunction1(it)
} ?: ComposableFunction2()

You can reproduce the issue creating a new Compose project using the wizard and replacing the Greeting function with:

@Composable
fun Greeting(name: String?) {
    name?.let {
        Text(text = "Hello $it!")
    } ?: Text(text = "Hello!")
}

If I use the old version 1.0.5 for both Compose and the kotlinCompilerExtension and the version 1.5.31 of Kotlin, everything works. If I switch to kotlinCompilerExtension 1.1.0-rc02 and Kotlin 1.6.0 the Text(text = "Hello!") does not run.

Of course I can fix the issue using if-else instead the (convoluted) let + elvis operator but I wanted to understand whether the new behaviour is documented somewhere. By the way, if I add the function:

    private fun testFunction(name: String?) {
        name?.let {
            Log.d("testFunction", "Hello $it!")
        } ?: Log.d("testFunction", "Name is null")

    }

everything works as expected even with Kotlin 1.6.0 that means that I see the log "Name is null"