Why do the dates regularly change on the Student Finance "Letters & emails" webpage?

Hello,

I've been checking the "Letters & emails" section on my SFE account for a few weeks now, waiting for updates on my current application. However, I've noticed the dates of letters/emails change arbitrarily?

For example, a week ago I would see a "Notification of Entitlement" letter sent on the 6th of October. The next day, this could then say it was sent on the 5th of October. This keeps happening with multiple items in this "inbox" and the dates keep changing for the exact same document? I also have letters appear one day that disappear the next. For example, I had a file called "Statement" show up on the Letters & emails section which then disappeared entirely a couple of days later.

Why does this happen? Surely if these letters/emails are sent on specific days in the past, how could the dates of these possibly change now? And why do documents disappear from this section altogether? I wish I downloaded the file as soon as I saw it now!

Thank you for any input on this; I can attempt to upload screenshots of the issue if this would help.