I have implemented this fix: $this->date = substr_replace( $date, '01', -2 ); and it fixes the problem where events are missing in the grid view if called by URL /events/months and there are corresponding digits in the day and month or year.
However I am still having a conflict (at least in my installation) with the sidebar Events List Widget.
When I turn the widget on, it appears in the sidebar and lists events correctly, BUT it breaks the gridview (in all cases) such that it no longer shows events (on any date) and the calendar it shows is not correct for the month. The List view works correctly.
No events appear in the calendar, AND the calendar for any month selected starts with Day 1 on Monday at the top left and goes for 31 days. No matter which month is selected via drop down or url. i.e. February 2010 starts Monday 1 and shows 31 days.
The example is here: http://develop.posseproject.ca/index.php/category/events/?$
But in all likelihood, I will have the "upcoming events" sidebar widget turned off until I get a fix. (So the calendar will otherwise appear to be working).
If you have any suggestions as to what I should look for in the code to determine why the conflict is occuring, or how to change the Sidebar Widget so that it doesn't break the loop generating the calendar - would be much appreciated!