So you can see that the cert that is presented is not trusted , therefore where is the CheckPoint HTTPS Inspection culprit ?!?!?!
As for the WebEx.com, it might do some redirects and will get to the 220.127.116.11 (that is webex.com.ro.webex.com.ro ) , you should run some HTTP network traces ( in Chrome do an F12 and choose Network Tab [mark Preserve Log] and you should see the 3xx redirects if there are any) .
Still I'm not getting your question, you state that you have HTTPS Inspection on the GW and on webex.com you get some browser SSL errors/alerts - where is CheckPoint part involved in all this ?
You have a bypass rule that it happens - is clearly showed/logged - and if the HTTPS would Inspect, you should see your internal Certificate generated on-the-fly from the GW .
So I didn't catch your CKP problem except the HSTS error - and that is not tight to CKP in my opinion.