For example, I check ET open/emerging-current_events and click Download & Update Rules, spinner spins, but not installed is still listed. After trying a bunch of times I was able to get ET open/emerging-attack_response installed, but it doesn't seem to install anything else consistently.
Running 25.7.7_4
Hmm, after about 10 minutes the rules that I attempted to download showed up as installed. I guess I just needed to be patient!!!