What was found
THE ACFT DEPARTED AND WHEN GEAR HANDLE RAISED, GEAR DISAGREE CAS MESSAGE SHOWING THE AMBER GEAR DISAGREE AND CYAN PROX SYS FAULT (NOSE GEAR INDICATION SHOWED STILL IN TRANSITION). THE CREW CYCLED THE GEAR WITH THE SAME RESULT. CREW FILED BACK TO DEPARTURE AND LANDED WITHOUT INCIDENT. THE ACFT WAS JACKED AND NOSE GEAR INSPECTED. EVIDENCE THAT THE GEAR UPLOCK MAY HAVE BEEN INADVERTENTLY CLOSED BY CLEANERS DURING THE PREVIOUS DAY DURING A ACFT DETAILING. NOSE GEAR CYCLED THRU 5 EXTENSION AND RETRACTION CYCLES WITH DC PUMPS WITH NO DEFECTS. NR 1 HYD SYS WAS BLEED AND 2 MORE CYCLES OF THE NOSE GEAR WERE COMPLETED. THE ACFT WAS DOWN JACKED AND RETURNED TO SERVICE. THE PLANE WAS THEN FLOWN. THE GEAR WAS PUT THRU SEVERAL MORE CYCLES WITH NO DEFECTS NOTED.