As of when I configured the first of three new children's iPads sometime in the last couple of weeks, it installed new apps according to the applied profiles and, including Apple's preinstalled apps, ended up with over 300 apps installed. The remaining two children's iPads have 91 and 98 apps installed and none listed as missing. Identical profiles and policies on all three iPads. When the apps still hadn't installed after several days and weren't even showing up in the SM client on either iPad, I dug further and discovered that the Dashboard only listed 46 apps total and only 24 with the "kids" tag! Where did all of the others go? I tried re-importing all apps from VPP but ended up getting a message about trying to add apps with IDs that already existed. I still only have 46 apps total listed in Dashboard (Android AND iOS combined!) and no idea what happened to the rest. While I would greatly prefer to get them all back, tags included, I could live with re-importing if that would actually work. Unfortunately, it doesn't seem to. Running the free version of Systems Manager with 46 devices.
Maybe try going:
Systems Manager/Apps
Then in the top right "Accounts" and then "Refresh".