Date Modified in Finder

You could QuickLook it instead of opening.

I looked at the Date modified time stamp of a Pages document that was last modified on June 30, 2023. I then opened it in Pages v13.1 on Ventura 13.5.1, and then quit Pages with cmd+Q. The date modified time stamp did not change, but intuitively, the last opened time stamp did.

However, without any changes to the document, when I instinctively clicked cmd+S to save it, then the date modified time stamp is reset to current time.

Lesson Learned wrote:

Thanks -- that's true, but doesn't answer the question as to why Finder isn't functioning as it should.

If I knew the answer I would have included it.

As with VikingOSX, I can't replicate your issue.

I thought if it was a cloud version, maybe downloading would cause a modification, but it didn't.

Maybe some 3rd party app (anti-virus?) does this for you when the others can not reproduce it?

But it still leaves me wondering why Finder isn't functioning correctly. That is made more interesting by the fact that under View in Finder, you can choose to either sort by Date Modified, or Date Last Opened -- which indicates Finder recognizes the difference!

Unknown why as it doesn't change the date for me.

Date Modified is file system data and Date Last Opened is metadata. Something is happing with your Mac that seems to write the file back to the drive. That's the only thing that would change the file system data.

Lesson Learned wrote:

Appreciate all the replies.

In providing the basic info in my OP, I neglected to say that I do not use iCloud, so the issue is strictly between the OS and the HD.

VikingOSX makes an interesting point, that I should have also included. That is, the issue does not occur when I open a document using Pages. It only occurs when I open one using Finder.

Finder doesn't open files, it looks at the selected file type, compares that to the System Launch Services database, and the default opening application for that file type, and then passes the request to the opening application. In the case of Pages documents, there are two applications (Pages, LibreOffice Writer 7.6.0) that can open Pages documents, but only Pages is listed on the Open With submenu. Actually, there is a third (e.g. Preview) but the Pages document is opened read-only via Preview's File chooser.

None of the applications in the the preceding paragraph has altered the modified date/time stamp of a same Pages document when opening it. If that were to occur, the Finder Window list view would automatically update to reflect a change in the modification date/time stamp and it did not. I used double-click, Open, and Open With and observed no modification date/time stamp change.

Reboot your Mac.

That said, I realize I can avoid the issue either by using QuickLook (as Barney-15E pointed out), or by opening documents using Pages.

But it still leaves me wondering why Finder isn't functioning correctly. That is made more interesting by the fact that under View in Finder, you can choose to either sort by Date Modified, or Date Last Opened -- which indicates Finder recognizes the difference!