Facebook notification “blue dots” not clearing when read on iPad 2 mini

I’m on iOS 11.4.1 (15G77) on an iPad 2 mini. I believe it’s since the last update that I’ve being seeing this. On the notifications tab, the new notifications appear as usual at the top of the list with a blue dot off to the right to indicate they are unread. However after reading the item, and coming back to the notification list, the blue dot does not clear. I do not have this behavior on my iPhone 7 running the same iOS version. If I read a notification on the iPad then look at it on the iPhone it will show as read. If I wait until the next day the notification read/unread dots will have synced up again. Anyone else seeing this or know of a fix? I’ve tried restarting iPad and reinstalling Facebook without seeing a change. Memory on the iPad has about 2 gb free. Thanks in advance!