Did any solution ever get published for this - interestingly I am getting exactly same behaviour in CRM 2016 for a custom entity. Refreshing the form with F5 creates a new record, instead of refreshing the current form and newly created record.
The record was created using the + on a sub grid so it opened in a new tab. We save (not save and close) the record, do an F5 refresh end up with a new record form...
One other irritating side ffect is that when we save the record there is no close mechanism on the form - the only way to close is to close the IE Tab....
I don't hold out much hope of an answer considering how long this post has gone unanswered but here's hoping... I will post an update if I work out what's happening in the interim...
Thanks,
Andrew
