problem with date/time and delivery of task reminders

problem with date/time and delivery of task reminders

Hi We are experiencing a problem which has been going on only recently, maybe the last 2 weeks or so.  We have all our activity reminders set for the same time every morning (9AM) but recently the reminders have not appeared in our email at the correct time.  Sometimes they are up to 6 hours late and then appear in blocks of 20 or so but never all together.

Additionally there seems to be a problem with adding reminders for some users as they appear with an end time in some cases and not with others.

Any ideas?