We are US citizens within Mexican permanent residency cards. We must have INM signed and stamped FMM cards to depart Mexico.
Upon return we have to show our portion of said form. When we arrived from BJX to TIJ, we easily found the INM office as we entered the baggage claim area. We were told by the INM officer that the CBX was not a border crossing and he point blank refused to process our FMM's!
The CBX agents tried to reason with him to no avail.
We crossed the bridge with great trepidation, knowing that we risked losing our residency permits without having the FMM processed for our return.
We did not return thru the CBX for that reason, choosing instead to hire a private car to drive us across the border to the airport. That worked--nobody checks papers as you enter Mexico, so as far as the government was concerned we never left their country.
We flew back home to Guanajuato.
Everything we read about the CBX is that it is a border crossing, so we do not know how in the world can the Mexican Immigration officer tells us otherwise and refuse to process our exit papers.