Mwan3: Strange observations

Doing extensive testing of switchover logic between 2 SIMs, used for one wwan only, I noticed following strange behaviour:

  • in mwan3.user, disconnected-event is received, before the route via this supposed-to-be disconnected interface is deleted.
    How can still there be a route (for couple of seconds), when interface is disconnected ?
  • in very dynamic environment, switching the wwan-modem on and off, I see disconnected event in the logs, but 'mwan3 interfaces' still shows 'online' . My own pings do not work, of course. How come ?
    I can imagine, a fluttering wwan because of bad signal might also trigger this (race-?)condition.
    For this to take care of, a safety net should be available in mwan3, to explicitly check the supposed-to-be online connection periodically, taking care of 'lost' events.