Random PDF's open with delay in Adobe Pro and Reader

We are seeing random PDF's that intermittently have a delay upon opening. This sees to occur no matter where the PDF is saved, their size and is not specific to particular files, one can have a delay when opening one time, then be completely fine the next, there is also no pattern to the order in which the delay occurs.

We have already disabled Protected View, App Containers and Enhanced Security with no success.