strange behaviour of a website on an iPad, but works on another iPad

hi. this is a strange issue:

My wife haS an iPad with IOS 18.5 installed. Javascript is on. she tries to login on a specific website:

-paprika

On the upper right there is a button "inloggen". (Login). If she touches it, nothing happens. I could not find a reason.

So I tried it in Firefox. Does not work either.

So I tried it on my Mac. that worked.

Finally I tried it on my iPad. That works too. that blew my mind out.

I cleared the cache and website data. I switched the iPad on and off.

I checked all settings to mine. they were the same, but maybe I missed one...

then by accident I rotated the iPad 90 degrees and the Login Form appears.......

again: this was not necessary on my iPad....

Any ideas?

[Edited by Moderator]