Main menu -> Mod Center -> Activate Mod -> Check map list when creating a skirmish
Map names are in the description

how do I load and play custom maps?

Let me know if it works, it seems updatemod.bat simply updates for the version but if you upload a second mod with the same name it updates the maps of the existing mod

Did an update that should have corrected it, I wasn't able to replicate that issue after the update. Which Scenario was it, and does resubscribing fix it?

there is a problem with you map , if you try play with friends game crashes for red side since they have no path for camera