multipe profiles on marshmallow: how to use apps in both accounts
I made a second profile myself to test if I'd encounter the same problem, which I did, and after googling a bit it seems the problem is caused if profile X does not install the exact same app version as profile Y. See this Reddit thread. As such it seems cross-profile app installation is best achieved by extracting .apk files, copying them to the other profile, and installing them there to make sure you have the same versions.