Even though you changed the COMMON Jumper in the rear of the module, the
Front End is still in COMMON START mode. The purpose of this jumper
is for the Internal 1/3, 2/3 tests [ F(25) A(1) & F(25) A(2) ] which
send the START & STOP signals to the front end at the proper time. To
change to COMMON STOP mode, you also must change the Jumpers
in each channel as shown in the manual and repeated here.