Outlook Webmail showing sender's name instead of receiver's name in Sent Emails

We are a community college with about 25.000 mailboxes, and only one is facing the following problem: After sending an email, this message is recorded in the folder "Sent items" as it should. But the "To" field shows the sender's name instead of the recipient as it should. The sender is the user itself, so what is the use of that? And the strange thing is: Outlook on the PC is showing it correctly, it only applies to OWA.

I've searched a lot but all topics found are about the Outlook client on a PC and has the solution to reset the view. But I'm looking for an option to reset the view in Outlook App on the web. (outlook.office.com)

What I've already found in other topics:

The options that the user would have imported the messages from an older client does not apply, always used Outlook.

What I already have tried:

Change the view, no solution

Settings - Mail - Layout, none of them provide a solution.
Creating a subfolder and move the message there, no solution.

Deleted all rules, no solution.

So, please help, Microsoft!