This is my first foray in to using Survey123, be gentle with me.
I've created a survey that will be used on both mobile (iOS) and laptop devices. I want to record the username of the logged in user who is completing the survey. I'm using Survey123 and have enabled the Inbox as I wish to edit records in an existing hosted feature layer in AGOL. In the XLSX Form (spreadsheet) I have configured the row to be of type 'username', and have entered 'property('username')' in the calculation column, as specified in the documentation:

This works great in the mobile app and the username of the logged in user is saved in the relevant field in my hosted feature layer. But when using the web form of the same survey on a laptop the username is not populated (even though the row is marked as 'required'). Why is this? How can I configure a form so that the username of the logged in user is recorded when editing existing records using either the mobile app or the web?