Is anyone else having issues with routers losing connection to ACS after upgrading to v4.5.0?

I updated 27 routers last week and since then then I am getting emails daily from a number of these routers showing that they have lost connection.
I can connect directly to the routers and they are not showing any breaks to the ISP.

No other settings have changed, the routers would all have been on v4.4.6.2 previously.

we have the same thing happening with a number of routers that we manage, one is sending upto 7 alerts a day at the moment and when we check the up time it hasnt dropped.

Seems to have been sorted in the latest 4.5.2RC firmware for the 2865 series at least.
Support at Draytek also recommended using the IP address of the server instead of c2.draytek.co.uk when configuring the ACS, same for connection detection, use the IP address of the server for the ping detect feature