APM RDP connection issue since upgrade 15.1.0.4

We have a dozen or so users that have direct RDP sessions to desktops via a webtop.

Never had any issues or complaits in the last year.

Now since updating to 15.1.0.4 from 14.1.2.3 staff have to click the RDP session 2-5 times to get the connection to establish.

Have tried a VPN session and manual connection via IP from a client and connected first time.

Clicked 2 times on the webtop RDP session before the session was interupted and the new connection taken over.

Not sure what logs I can investigate but am assuming its some sort of new bug as there have been no changes other then the update.