non admin can edit document - sync issue

tibr

Hi,

I noticed this synchronisation issue:

I'm in a group as an admin. Person X is a member who can (theoretically) only read the library.
We have a powerpoint presentation in our library. If I edit it, changes appear to person X, which is fine.
The problem is the following: person X can open the powerpoint and modify it, without any warning. The changes do not appear to me, which is ok I guess, but if I then try to modify the presentation, the changes I made do not appear anymore to person X.

Is this normal ?

Tim

tibr

Hi, I just reiterate my question from a few month ago. Does anybody have any info on this ? how to prevent it ?