We have noticed with the recent release of Indesign 2017.1 master pages elements don't show up when you first open the file. You have to apply master page items to see them. Is this a new bug?
It's not just one machine we have 3 studio macs which are showing the same and also client machines which have updated to the latest release. It's fine on 2017.0
I haven't experienced this either, John.
All Macs? What OS? Any Windows systems involved? All files or some files?
If you think it is a bug, you (and your clients) can report it here (click the Bug Report radio button):
Wishform - Adobe InDesign