Schedule events intermittantly display on wrong day in week view in My Workspace

A user is a particularly heavy user of the schedule tool. He will usually have 7-8 events per day in the site schedule, including several that overlap in timing.

He has noticed on at least 2 occasions that, in the default 'calendar by week' view, events will display on the day after the correct day. Clicking on the event to see the details shows the correct times. The support team have seen the site and can verify that this is exactly what's happening. .

Although this problem occurs happens rarely, this is causing serious problems for the users, since it means that users can't rely on the schedule as they see it.

Events display at the correct time in print view, and in day and month views.

The problem can not be reliably reproduced. It appears to be connected with having multiple events on simultaneously, but adding in events with the same dates and names to another site does not reproduce the problem.

Events can be made to display on the correct day again by deleting (and then re-adding) other events from that day.

We would be very grateful for any pointers about what might be going wrong.