Issue with SerialCancelable in Monix 2.1.1

serial_cancelable.scala

import monix.eval.Task
import monix.execution.Scheduler.Implicits.global
import monix.execution.cancelables.SerialCancelable

val ref = SerialCancelable()

val t1 = Task {
  Thread.sleep(10000)
  println("Task 1")
}

val t2 = Task {
  println("Task 2")
}

val combineTask = for {
  _ <- t1
  _ <- t2
} yield ()

val t3 = Task {
  println("Task 3")
}

ref := combineTask.runAsync
ref := t3.runAsync

// Monix 2.0.0
//
// > Task3
// > Task1

// Monix 2.1.1
//
// > Task3
// > Task1
// > Task2