Summoned mobs have no equipment

Noticed this bug since 15w32a onwards. I've been making a custom map so I've been having issues with the /summon command.

In particular, when I use a summon command that should summon a mob with full armour and holding a weapon, none of the equipment appears at all.

I've already gone as far as deleting everything but my save file and trying again but it does not seem to help.

I thought it might be due to an error in the world file, but as you can see in the third picture (taken in the quartz super flat, in fact, before taking this picture I deleted all but the save folder once again) it is not limited to only that world.

I hope this can be resolved soon.

Thanks,
JhonCo