Help (Tmobile) Calendar Notifications Don't Dismiss/Android 4.1.2

[biz_kid1]

My calendar notifications won't "Dismiss" but they "Snooze" OK. It's a brand new phone (got it this week) and I can check one (or all) notification(s) then "Dismiss" and the dropdown disappears but when I check again, the notifications I dismissed are still there.

No updates are needed and a reboot didn't help. Am I missing something?

Thanks in advance!