Cannot goto day in top right month calendar for some dates with some attempts not providing selection-highlight

[wmlake01]

In month view or day view, selecting a specific day date in the top right calendar only works for part of the first week of December.

The function of selecting a day in the first week provides selection highlight feedback with no action for dates Nov28-30, but it does work for the dates for Dec 1 thru 4 (the rest of the first week). It provides no highlight and no action for any dates in later weeks in December. Other functions of the calendar in the top right appear to be working as they should, such as selection the month, ie fwd/back/R buttons.

If I go back to November overview, I can select any day, with highlight feedback but the page does not change.

I don't know what triggers the issue, however my calendar is configured with two special days on the Dec calendar (12/9, 12/25) and headers: W#, M-Su,Re. Also, earlier in this session, I had tried to select a day-date with the stencil, out of habit (which never works), and it drew a dot. I think I have seen this cause a similar error in the past, but not sure. So I area-erased over the calendar to remove any dots in an effort to fix the issue with no effect. I tried close and reopen file.