Ran into this exact same issue a few weeks ago, where I had ActiveAdmin updating records but the Sweeper wouldn't observe the model on normal CRUD. I attempted to have the sweeper get called as an observer but I still couldn't figure my way around it, so I fell back to using Rack::Cache (and updated with suggestions from Ryan's screencast earlier in the week).
"…an example that's a little more practical than launching rockets."
Some would argue there are few things more practical than launching rockets!
Ran into this exact same issue a few weeks ago, where I had ActiveAdmin updating records but the Sweeper wouldn't observe the model on normal CRUD. I attempted to have the sweeper get called as an observer but I still couldn't figure my way around it, so I fell back to using Rack::Cache (and updated with suggestions from Ryan's screencast earlier in the week).