In RM, when I use time as a rule trigger, the time picker screens, both the analog and digital time pickers, are missing the OK and Cancel buttons. Therefore, I can't specify a time. Annoying but not a show stopper since I can use the PC app.
When I connect my hub for management services such as RM management, I'm actually working in a web browser (it is sometimes easy to forget that fact). By default I use DuckDuckGo and that's where the problem happened. It occurred to me to try a different browser, in this case MS Edge, and everything worked correctly with the date picker.
The obvious conclusion is that browsers matter. Mainstream browsers like Edge, Chrome and Firefox probably all work fine, but niche browsers such as the privacy-centric DuckDuckGo did not - a good thing to always keep in mind...
Should work ok with Brave browser as well. I've never had any issues with it in that regard. That way you can still keep your privacy. By default, it uses their own Brave Search engine, which is still a bit, ummm, underdeveloped at the moment, but you can change it to use duck duck go if you want.
I'm not too concerned about privacy when in RM because traffic is local to the hub and behind my router firewall. It just means I have to temporarily switch from my default DuckDuckGo to an alternate browser when I occasionally run into a compatibility issue like this one. So far this is the only case I've seen where there is an issue using Elevation with DuckDuckGo.
Hopefully this thread will be helpful to anyone running into similar problems.