It will be rather hard to reproduce this error (as for me it required custom constraint on Stores on Product add/edit page in Drupal commerce). Easiest way to see exactly same markup as I did, would be to have any checkbox in node edit with added "error" class to it (easily can be done by modifying markup in browser)
Real issue here is that after having validation error of field with checkbox/checkboxes we lose possibility to see changes after changing its "checked" state - it simply always looks the same no matter whats the state (see "original look.png")
Here I provided really simple patch for that (it changes way inputs with error look - see "after patch look.png"), but you should be aware, that this is simplest solution to this issue I found and it for sure can (and should) be done better.
