Is there any impact on outlook sent item folder by turning on Exchange cache mode

[kuenzeey]

There was an inquiry from user that "Group" is not displayed in the mail folder of Outlook(desktop application).
As user said that there is no problem for the version ,so, we let user to set "Exchange cache mode" to "ON".

After setting "Exchange cache mode" to "ON", later user noticed that some of the sent items are not saved in sent item folder.
(According to user, it said that the items of 2021 was not there but the items of 2022 and 2020 was there in sent item folder
and this problem was caused both in web and desktop outlook).

So, my question is
Is there any impact on sent item folder(Both web and desktop outlook)by turning on Exchange cache mode?
I checked on my outlook but there was no impact on it, everything was fine for me.

I would be grateful if somebody could confirm me about above problem.

Thanks in advance

[#2]

Check whether he can see all the "missing" Sent items in OWA. If everything looks OK therein, recreate the Outlook profile, with the cached mode setting toggled on from the start.

[#3]

vasil thanks for the response.
You mean to say outlook web application?
yes the user recreated his outlook profile again and still there was no change at all.
Checked on outlook web app and user said that it was missing from outlook web app too.

[#4]

If they're missing in OWA, they're either moved to another folder (does the user have an Online archive enabled) or gone for good.

[#5]

hello Vasil, yes it seems like the user has enabled his online archive.
So checked archive folder under online archive but nothing was there.
Are different way to access online archive ?

[#6]

Ignore the "Archive" folder, check the Sent Items folder under the Online archive node.