Strange VPN Client behaviour after waking from Standby

[embeeweezer]

Since a while I noticed that my VPN Client (running the latest version) has trouble reconnecting to the server after my laptop (Windows 8.1 x64) resumed from standby mode.
VPN Client says it's reconnecting, determining the IP (which is strange since I use fixed IP's), and then it 'reconnects' and the client status is 'connected', but:
- windows says 'Cable is unplugged'
- no ip connectivity exists over the VPN
- sometimes the VPN Client gives me the message about UDP Hole Punching / Server behind double NAT (which is NOT the case!)
Anyone else experienced this behaviour and was able to fix it? I have no clue...

edit:
I can reproduce the problem: while the vpn client connection is 'connected' and I disable the adapter in Windows, wait a moment and enable the adapter again, the problem arises.
When I *disconnect* the client before disabling & enabling the adapter, (and manually connect the client again) there is NO problem.
Still this is not a solution of course...

to sum it up:

scenario 1 - working condition - computer goes to sleep - computer wakes up - vpn client searches for ip (?) - says connected - adapter status 'Cable disconnected' - PROBLEM condition.

scenario 2 - working condition - I disable the vpn adapter (in windows) - I enable the vpn adapter (in windows) - vpn client searches for ip (?) - says connected - adapter status 'Cable disconnected' - PROBLEM condition.

scenario 3 - working condition - I disable the vpn connection (in vpn client) - I disable the vpn adapter (in windows) - I enable the vpn adapter (in windows) - I enable the vpn connection (in vpn client) - vpn client says 'IP x.x.x.x is ready to use (so no 'searching for ip' message) - says connected - adapter status 'Cable disconnected' - NO problem condition.

Thanks - Mike.