hi glids,
Looking at the drawing, you have a C/R filter on pin 11, the clk line.
The 4013 requires a clean, fast rising edge, to make it toggle.
If the clk edge rises 'slowly' the 4013 will switch erratically.
Also at 3.6Vs, its working close to its lower limit of 3V.
If you put your scope on pin11 [use +10 probe], you will probably see a slow clock edge.
Also scope the output of the 4013, when you send the trigger pulse, I suspect it will be rapidly switching during the clk edge period.
You may require a schmitt ic. something like a 40106 with a C/R filter, this should give you a clean edge.
EDIT: attached drawing.
Eric