I am experiencing this as well on both "All" and "Images". It happens on every search query I can find.
This is happening on my Firefox on Desktop, however it works fine in Firefox on my Android device.
I tried multiple different firefox profiles, I disabled uBlockOrigin.
The behavior is that it shows the URL saying the modal is there, but it's not. if I hit escape on the keyboard it acts like it's closing the modal.
I have not tried in other browsers on my desktop (I do not have Kagi configured in them as I do not use them unless I need something "Stock" for very rare compatibility issues).
Firefox did just push an update to version 145.0 - but given the other user is on Brave it may not be related.