Unless it is the chair-keyboard interface not functioning within established parameters... promotions seem kinda flaky.
The promotion I created worked on my admin acct, but not for a regular test user, However, after deleting the promotion and adding the exact same one again (and running manual cron again)... it then worked for the test user.
EDIT: I unchecked the newly enabled secondary usergroup ('members') on my test user, ran manual cron again... and now it does not check the box again. I then deleted and added the promotion a 2nd time, ran manual cron again like above... and it worked fine again.