Akka traces aren't being generated (Scala)

Description
Akka actor traces are not being generated

Steps to reproduce
HTTP GET request (curl -v http://localhost:8080/test) is triggering ask call:
val result = testActor ? Message("test")

TestActor replies after sleep.

  override def receive: Receive = {
    case Message(x) =>
      Thread.sleep(1000)
      sender() ! ReplyMessage(s"$x - reply")
  }

See https://github.com/makssobolevs/akka-open-telemetry-test

What did you expect to see?
I would expect to see both akka-http and akka traces for single http GET request.

What did you see instead?
I see only akka-http traces,

[otel.javaagent 2022-01-15 17:54:05:901 +0300] [Test-akka.actor.default-dispatcher-5] INFO io.opentelemetry.exporter.logging.LoggingSpanExporter - 'akka.request' : 6a4300eaa53f60b80ae33e87e937d7bc 6213f1d2d19da9ec SERVER [tracer: io.opentelemetry.akka-http-10.0:1.9.2] AttributesMap{data={thread.name=Test-akka.actor.default-dispatcher-5, http.method=GET, http.scheme=http, http.host=localhost:8080, thread.id=17, http.target=/test, http.user_agent=curl/7.80.0, http.flavor=1.1, http.status_code=200}, capacity=128, totalAddedValues=9}

no traces related to TestActor

Version
opentelemetry-javaagent 1.9.2
Akka 2.6.14
Akka HTTP 10.2.4
Scala 2.13.5
OpenJDK 11.0.13

Start with the linked akka-open-telemetry-test example, the HTTP GET to /test, and TestActor.scala, especially the ask call and receive handler. Reproduce the request with curl and inspect the agent output. Done means the single request produces both akka-http and TestActor-related Akka traces.