I got the information that app's behaviour is the specification. the issue is resolved.

Yesterday, I updated my iPhone SE2 to iOS26.5. But issue does not resolved.

Thank you for your reply. At first, I asked my question on the Apple Support Community. However, I was advised to post it on developer.apple.com since my environment includes beta software, I also submitted the same issue through the Feedback Assistant, but I have not received any response from anyone. Since it seems that no one else is experiencing the same problem, I am planning to reset my iPhone.

Today, I confirmed that the Pages and Keynote apps are causing the same error. I can't view the files of these apps on my iPhone.

I could preview these Numbers files on iPhone6s(iOS 15.8.7) without Numbers app. iOS is too old, I could not install Numbers app.