Customer Portal "Where I am Request Participant" search is not working

In my customer portal, I used a customer account to create an issue.

Then I shared the issue with a Gmail address.

The Gmail address received an email about the issue being shared. On a mobile phone, I clicked on the View Issue link, issue is displayed.

But then, still using mobile phone, I clicked the Requests button in upper right, choose All, and nothing was displayed. I changed the filter to “Where I am Request Participant” and still nothing. I cleared all filters and still nothing.

I clicked the View Request link in the email and it still works.

Why?