Issue with DNS resolution in browser when connected via Checkpoint mobile client

[sklotz]

Not sure if this is really a VPN and/or Checkpoint issue, but as of now it looks like with the following strange behavior.
When users are connected via VPN and browsing websites with internal DNS-names, the browser sometimes through the error message DNS hostname could not be resolved. Also ping the hostname is affected. Only a dedicated nslookup is working fine.
Our first idea/finding was that it might be related to a missing metric entry for the VPN-adapter, but setting this metric manually didn't change anything.
Then we tried to sniffer the DNS-queries on the Checkpoint FW (which terminates the VPN) and we see both the DNS-request as well as the response once we hit refresh in the browser. This means the client is sending the DNS-querie via the correct interface, but it looks like the client (browser or ping) doesn't react on the DNS response.
Do you have any further idea how to troubleshoot or analyze this issue? Or do you already know, what's the reason for this?
We are running on 81.10.
Thank you!

Regards,
Stefan