This used to work without issue .. prior to a few days ago, my son was able to see and place command blocks without issue. Now he can do neither, and I find that the 'op' command is missing. My first guess is that you guys were phasing in some other way to confer this ability on my guest .. is this the case?
Guess number 2: this is a bug .. 🙂
This issue is being tracked in REALMS-1511. A fix is in the works.