Strange behaviour of Windows search box on taskbar

I tried SelinaKnow's suggestions. First of all, both PCs are signed in with a local account and the region/language settings are English UK on both.

I executed the Powershell command on both:

On the one with the changed behaviour, it reports the version as 1000.26100.360.0 and on the other it is 1000.26100.344.0, and there are no other differences apart from the corresponding one in the package full name. Those version numbers match the "Windows Experience Pack" version in Settings->System->About. Both PCs are running Windows 11 Home 25H2 but the version is 26200.9457 on the one with the changed behaviour and 26200.9168 on the other. Thus it seems to me that one of the recent updates has changed the Windows Experience Pack ; however, the only updates installed recently are all shown as security updates, and one would not expect them to introduce such a change. I will look into submitting things via the Feedback Hub when I have time.