Personally, and having noticed this interesting piece of info myself, I have to say this is a major reason I believe Martin DID in fact turn around and confront Zimmerman, and why I believe Zimmerman's self defense claim.
I think it's possible Martin simply lingered in the area and when Zimmerman went through the cut through that Martin had just took he assumed Zimmerman was still following him when Zimmerman was just going back to his vehicle. Martin then confronted Zimmerman and the physical altercation took place almost immediately.
If you'll bear with me, this is where Zimmerman was most likely parked, just north of this address here just before the bend in the road to the right.
http://maps.google.com/maps?q=1220+...20+Twin+Trees+Ln,+Sanford,+Florida+32771&z=19
Zimmerman
(expletive) he's running.
Dispatcher
He's running? Which way is he running?
Note that at where Zimmerman is stopped he would lose sight of Martin almost immediately if he ran straight east but it would appear that he has turned towards the rear entrance. At this point he gets out of the car to see which way he is running, but note that this isn't until the dispatcher asks which way he is running
Zimmerman Down towards the other entrance to the neighborhood.
Dispatcher
Which entrance is that that he's heading towards?
Zimmerman
The back entrance
(expletive)(unclear)
Dispatcher
Are you following him?
Zimmerman
Yeah.
Dispatcher
Ok, we don't need you to do that.
Zimmerman
Ok.
At this point you can hear Zimmerman's breathing gradually return to normal. If he jogged at average speed at this point he is possibly directly north of where the shooting eventually took place. He also possibly has just seen Martin turn right directly
(EDIT: northeast) of the housing unit which includes this address.
http://maps.google.com/maps?q=2811+...eat+View+Cir,+Sanford,+Florida+32771&t=h&z=19
In my opinion Martin most likely lingers in the cut through directly south of that address. Note that the home of Brandy Green is one of the units south of the unit directly south of where he might be at this point.
In my opinion the mostly likely scenario immediate following this given Zimmerman's account as well as Martin's girlfriend's is that Zimmerman knocks on the doors of the housing unit north of where Martin is lingering, headed south. Martin doesn't see Zimmerman at this point so continues home slowly between the housing units towards Brandy Green's back porch. After Zimmerman has hung up with 911 he heads back to his vehicle taking the shortest route, which is through the cut throughs. When Martin sees Zimmerman where he was just lingering he assumes incorrectly that Zimmerman was still following him, prompting him to confront Zimmerman.