Hello fernando.barrios@uwaterloo.ca,
I tried to replicate your use case and the result was successful: the PWM period is 100ms, as you can see in the image attached. For the CH4(PD13) I used a duty cycle of 25%(0.25) while on the CH5(PD14) I used a duty cycle of 50%(0.5).

The duty cycle must be provided as "single" data type values in the interval [0.0, 1.0], proportional with the percentage of the duty cycle. This makes easier the usage of the PWM blocks alongside with the AMMCLIB blocks.
As a suggestion for your issue, please be sure that in the General Tab of the PWM blocks, the checkbox "Start PWM signals generation immediately after initialization" is checked because your board might not start the PWM and no signals generated. To be honest with you I don't think I understand your LED testing mechanism, so if the problem continues please consider attaching your model here and I will have a look.
I am waiting for your response!
Best regards,
Marius