Thank you, that BOC was not checked, I will try that tomorrow!

Good point us7070,  I didn't notice that before.

I checked my event log and this is what happens:
- Auto mark advance seems to work fine for all marks of an active route, except for the last mark of the route.  For these marks (except the last mark of the route), there is only 1 entry in the event log.   The column "minutes" shows a number > 0 but I have no idea what it means as it is definitly not the number of minutes that my boat was within the specified mark range  (e.g. it says 92.3 minutes while I was only within the range a few minutes;   I use an auto mark advance  range of 0.15 miles)
- For the last mark of an active routethere is indeed an entry in the event log every second.  This seems to be going on for the duration that you sail within the auto mark advance range of that last mark. Then it stops adding entries to the event log.  New entries start appearing once you have activated a new route and you pass the first mark of it.

@Nick:  can this be addressed?

i am seeing it at more than just the last mark

my auto-advance is set to 0.1nm