In this beta, the execute command is no longer allowing executed entities to summon things.

Here is an example of a command which I use all the time which has now broke.

/execute @e[name=Vampire] ~~~ detect ~~~ air 0 summon skeleton ~~~

This command should make the vampire named mob summon a skeleton, however in this update it comes up with the error "unable to summon object as Vampire"

Please fix this