I have a 6 zone spinkler system-- only 3 are being used. Zone 1 comes
on first and is suppose to shut off for zone 2 and zone 3. Zone 1 does
not shut off when zone 2 runs or when zone 3 runs. It finally shuts
off when zone 3 is done. In other words, zone 1 runs for the length of
the watering, while zone 2 and zone 3 take their respective turns. Any
suggestion on how to approach this?

I don't know the name of the spinkler system. I moved in 2 years ago.
Their appears to be a door to the controller that was removed. I
assume the brand name was on the door because it is not on the main
frame. It is a tan plastic with 12 round dials to set things (2 dials
for each station-- one for duration and one for days).