So good comments everyone! Starting with Und1's answer up top, I agree the most obvious problem is the maglock being used is meant for securing one door, not two.
Here is a results snapshot showing about half of total votes concur:
Simply stated, a magnet is only as strong as the bond it creates. In order to create the strongest bond, the armature (also called strike by some) must be in full contact with the magnet.
Downrated Bond Force
In the case of the door above, it looks like the armature was cut into two pieces, one for each door, but done in such a way that each armature only contacts ~40% of the magnet surface.
This means that the individual bond strength of just that door is downrated significantly. If that particular magnet is rated at 500 pounds of bond force, 40% of that rating is 200 pounds.
This means that each door is only being held secure by a fraction of the designed rating of the maglock. The OP is able to yank a modest amount and break the bond by hand. Not good!
There are other factors at play here: for example, the way the magnetic field propagates assumes the armature is a solid piece. Cutting it in two introduces an air gap (between the doors) that acts as a dielectric essentially weakening the max possible bond.
Also consider those conference room doors are quite tall. The fact a user can grab the door handle and essentially use leverage over about 4' - 5' of the leaf to pry the lock apart is another reason to use strong locks, especially in this application. Just image if a user jammed a crowbar of the same length between the armature and magnet. Popping it off wouldn't be difficult for a weak magnet!
When specifying maglocks, the height of the door needs to be factored into the bond rating. If the door is taller than 8', taller doors need stronger locks.
This is where frame features like mullions and door hardware with strike latches can improve door security. Beyond just a latch alone, they make the door more rigid and harder to flex.
Better Maglock Solutions
Now, there are examples of 'split armature' maglocks, but it should be noted those units are designed with high bond, individual coils and armatures to mitigate exactly this sort of weakening, or they disclaim the resulting weakness. (Another one) These beefed-up units tend to be expensive, in many cases 3X the cost of a basic single armature model.
It is much more common to use two single maglocks, or dual maglock units like many of you have mentioned.