I am sitting here at my desk with my car.
If I push down on the right front corner, pushing on the shock tower just above the right front shock mounting location, the right front goes down, the left front goes down slighly less, and the left rear is unloaded slightly, but surely not coming off of the surface of the desk.
The only way I can envision your senario taking place is if the the left front has no uptravel, and your pushing down on the right front is making the left rear pick up off the ground.
You could also have excessive pre-load on your front springs, with would keep the left front from compressing when you are pushing down on the right front.
If you doing the follow things:
1. Remove all the droop screws.
2. Remove all the up-travel limiters.
3. Adjust the threaded shock collars to the point whrere the chassis is 5mm off the ground. This is the thickness of a spur gear, in case you do not have a ride height guage.
4. Check that each of the shocks will compress individually. Not overfilled with oil, etc.
5. Check that the suspension on each corner of the car operates freely with the shock removed.
If all of the above conditions are in check, then the condition you describe cannot occur.
As I stated before, some pictures would be very helpful.