I created an object and used the Timer behavior. This was the setup:
On start of layout --->
+TimersObject: Start Timer: "timerPlane" with length 4000 ms (...)
+TimersObject: Start Timer: "timerAero" with length 20 ms (...)
The result was that the same length was used for both timers.
I tried a workaround for the bug, adding ANOTHER timer behavior to the same object. The results were the same: I still got only one timer length for both timers.
Right now my only option was to add 4 sprites, each with their own timer behavior. That seemed to work fine.