iPadOS Safari can operate in two modes - the default Desktop mode or Mobile. The browser User Agent, as enumerated by the website, determines how the website is rendered in your browser.
When iPadOS 13.5.1 Safari used in Desktop Website mode, your credit card company believes that your browser is Safari 13.1 on macOS (Catalina).
Here is an example:
https://discussions.apple.com/content/attachment/8319e590-4792-4245-8432-1ad307e01fe1
By contrast, if you switch to Mobile website mode, your User Agent is instead detected as Safari 13.1 on iOS 13.5:
https://discussions.apple.com/content/attachment/67bea885-63d3-4c71-a6d0-31333b131849
What is the difference I hear you ask...?
Many websites are optimised for either full-sized screens, or smaller screens such as a mobile phone. Some websites will cater for both - and will produce an optimised page for both types of device - this being determined by the detected User Agent that is accessing the page.
You can switch browser modes using the options menu accessed from the aA icon that you’ll find at the left end of the Safari Address Bar. If a website doesn’t like the current mode, try switching to the other; touch the aA icon, select Website Settings - and deselect Request Desktop Website, then tap Done.
I hope this information and explanation is helpful in clarifying the observed behaviour of your iPad.
