Recurring Event Issue

We’ve noticed an issue after setting up a recurring event and viewing it WP Full Calendar via a short code. We’ve tried the new release of WPFC with the same results

Plugins Used
WP Events Manager 5.9.2
WP Full Calendar 1.2

All tests were setup as recurring events every Tuesday for a year starting from today’s date.

Test A (localhost – PHP version 5.3.13)
1) use the fullcalendar shortcode on a page.
2) View calendar (Months looks good and then the calendar is off beginning in November).

Test B (server – PHP version 5.3.3)
1) use the fullcalendar shortcode on a page.
2) View calendar (First month looks good and then the rest of the calendar dates are off OR missing in varying months).

It appears part of the issue is related to the following link:
https://php.net/manual/en/datetime.modify.php

We made a change in em-wpfc.php in the way $scope_end is created using $scope_start as a guide and it appears to have partly fixed the “Test B” issue. Even with this fix, around November, the calendar dates shift incorrectly.

$end_DateTime = new EM_DateTime(substr($_REQUEST[‘end’],0,10));
$scope_end = $end_DateTime->getTimestamp();

Note: We only tested and attempted to fix the issue described above. There may be others, but it appears something with the date calculations might be off for those with older versions of PHP.