Basically since dispensers don't put commandblocks down anymore, some maps in the minigame section of realms, donot work anymore.

Easiest fix would be
https://www.youtube.com/watch?v=Ccftx3EbzpM
Just go into each world, select the dispensers and hit filter.

Or you ask the mapmakers nicely if they would like to include a fix.
Or you remove the maps from the list and add new ones.

Either way, you can't fix these maps yourself, because in the minigame section nobody is opped so you can't fix it yourself.
The way we would have to do it is downloading the map ourselves, including a fix and upload it to one of our three existing worlds...

Broken maps include:

• Missile Wars by Sethbling
• Diversity 2 by QMagnet (not a minigame, -> preset)
• Memory Battle