Notes have gone missing between Galley and Page view

Just noticed this odd thing:
The Oboe/Clarinet G in bar 13 appears as it ought in Galley view

But is missing (last bar of left hand page in Page view.

How do I get it back?

That’s very odd – I can’t offer any immediate explanation for what might be going on there. Could you please upload the project itself so we can take a look?