Ok, so I did some more testing last night and I have concluded the following.
My NSPanel Pro can successfully display the ambient temperature and the temp setting of individual valves as well as changing the temp setting, EVEN when the valves are joined to the Bridge. However, it’s doesn’t seem to be able to display any of this with Groups. Changing temp setting works fine (and it’s transmitted to the device), but next time I go into the Group, the setting has been reset again, it doesn’t remember or are able to read the current temp settings.
I also joined the valves directly to the NSPanel Pro, and created new groups, but this doesn’t solve the issues with groups described above.
Groups (of valves) in eWeLink app doesn’t show temperature (not even when they are using the same external temp sensor), so that’s why I guess the NSPanel shows zero temperature when I select a group. However, the current temp setting for group should definitely be there.