Safari

I’m having an issue with Safari on my iPad Air 4 with IPadOS 15.

My doctor’s web portal has a section for communicating by sending and receiving typed messages.  The page is like a form where from a pull down list you select your doctor’s name, and in a text box you type in the subject and another text box where you type in your message.  When I open the message page, the form appears for half a second then the form disappears.

I have cleared the web history and data.  I have also reset the iPad settings.  Neither of these have solved the issue.

I have the Opera web browser on this iPad and it does display the message form

I also have an iPad mini 4 with iPadOS 15and an iPhone 8 Plus with iOS 15. Both of these devices show the form correctly when using Safari.

What could be the problem with my iPad Air 4?