When you create a session for an event, the session time is persisted by using the UTC equivalent of the time.
Currently the UTC time is being displayed in the administration portal instead of the effective local time. This impacts sessions which occur during British Summer Time (BST), but are created while it is not BST (when it is GMT).
If you edit a session which occurs during BST the time will shift one hour earlier.
This also impacts downloaded ICS files (used to add the session to your calendar). For sessions which occur during BST these will currently be added to the user's calendar with the incorrect time (e.g. at 8am instead of 9am).
As a workaround for the administration portal display issue please ensure that when you create or edit a session that you always use the correct effective time (so if the session will start at 9am always use 9am - ignore the impact of daylight saving time). This will ensure that when the issue is resolved the correct dates are displayed in both the administration portal and when a user downloads an ICS file.
This issue impacts version 3.5 of the LMS.