Entity registration still appears to be causing a few problems, the most prominent being that it seems to be impacting on the functionality of spawn eggs.

This method here appears to be the one that EchoPet is interfering with. It's likely a problem with the modifications that are dynamically added/removed where necessary in this method. Consequently, the map modifier probably isn't working as it should.

I haven't looked into it much beyond that, but I'm reporting it here in case anyone else has any other information.

@cindyker should be fixed now :)