I'm having 1hr problems too.

With it toggled on, if I then move the map to a different location, the updated forecast reverts to 3hr. I have to toggle the 1hr option off and on again.

I've been noticing this bug for a while: after each version update, the 'remember 1/3hr setting' (which I think is a Premium option?) gets turned off. It's not something I can test or replicate, because of how it only happens with a new version update, but it's proving to be consistent.

Windows 11, occurring both in Firefox and Vivaldi browsers.