Step to reproduce:

1. Go to any page that having help icon (e.g: Create course page).
2. Click on help icon, help dialog will be opened.
3. Close dialog using "Escape" key.
4. Click on the same help icon again, now we cannot open the help dialog.

Note: It's still working if we close the dialog by using tab key or click anywhere on the page.

Update:

Change the line theme/boost/amd/src/loader.js:56

From 

jQuery('body').on(customEvents.events.escape, '[data-toggle=popover]', function() {

    jQuery(this).popover('hide');

});

To

jQuery('body').on(customEvents.events.escape, '[data-toggle=popover]', function() {

    jQuery(this).trigger('blur');

});

Seem to fix the issue, I'm checking if it causes any side effect.