This was cross-posted in another forum:

The issue was resolved for this client by "Setting the default timezone to UST and forcing the timezone for all users".

This problem is a known issue and we have spent a bit of time looking into a fix for it. We have't yet been able to get it to reliably give the correct date.

Since this problem is bigger than just daylight saving our approach to try and fix this is to add a timezone selector to the face to face session date/time. There are then complications between server and client having different timezones set. We will have another look at this in the next week and see if we can come up with a solution.

Simon