Mwan3-hotplug and openvpn: Interrupted system call at disconnection

we use OpenWRT with tdt and teltonika devices.
With all the releases (since 2018) one problem is ever the same:

  • Two internet connections are used from mwan3. Normally wan is used and wwan (mob1s1a1) is connected but standby.
  • OpenVPN is using the connection as client.
  • If wwan is shortly or lang disconnected and connected again, mwan3-hotplug sends "Execute disconncted event on interface mob1s1a1 (qmimux0)" as user.notice.
  • OpenVPN then restarts the connection with daemon.err: event_wait: Interrupted system call (code=4).

But this is not necessary to do this, because wan is still connected. OpenVPN drops the connection shortly and connects again.

Who has got an idea not to restart OpenVPN on disconnect/connected wwan?

Many thanks