Apple Password app in iPad just comes up with blank screen although Password works to retrieve and use passwords.

I can retrieve and use passwords OK from the app. In Settings it shows the same number of entries as my iPhone does.

But when I open the app it just gives a blank white screen. In my iPhone (13) it works perfectly well and I can see and edit password entries via the app. But not in my iPad.

Both are on ios 18.1.

I have tried turn in off sync, powering off iPad, powering on, turning on sync. Makes no difference.

Any ideas?