Originally Posted by Ianus

It shouldn't take long at all. The officer should be able to make a decision as soon as the evidence is seen. You should receive an update almost immediately after.

On it being common, AOS takes around 4 months to just over a year. It should come as no shock that such a regulation would not be implemented smoothly. The procedure(AOS) takes a bit of time.

In fact, I would anticipate the same issues for the new I-485 form in August. It will likely result in more delays in the fall/winter as USCIS officers have to issue rejections because of the incorrect form.