I've done some searching and not been able to find anything about this either on the forums or tracker (a post from a few years ago about the same issue in the old dashboard block).
Moodle3.5, Linux servers, custom theme - but issue in all themes, custom version of the MyOverview block - bust tested in the standard block with the same issue.
My current situation - When students are granted an extension for an assignment, that extension date is not picked up by either the calendar or the Timeline view of the MyOverview block on the dashboard page.
This is causing significant usability issues for some of our disabled students.
Am I missing something, or is there a way to get individual student extensions to show in the calendar and timeline? If not, surely this is a fairly major bug - yet I don't seem to see anything in the tracker (happy to add one if I get confirmation that it is a bug, not me being daft and missing something obvious!).
I'm happy to make code changes to plugins - less so to hack core code, for obvious maintainability reasons, if that's what it takes.