Document Changed Message on Save

Hi

Today I’ve had a couple of instances of:

'This document’s file has been changed by another application since you opened or saved it?..
…The changes made by the other application will be lost if you save. Save anyway?

Has anyone experienced anything similar?
Can anyone enlighten me as to w.t.f?

Ric

Is the document stored in a synced folder (e.g. Dropbox)?

Hi Nik

No it’s not. just a folder in users.