Unfortunately I do not know how to easily use the sources-jar inside Android Studio and therefor I am not able to set breakpoints (I am using the jar with the compiled sources)
I recommend researching how this can be done (if it can be done at all). Otherwise you won't be able to determine the cause of your issues. I try to avoid using Android Studio, so I can't tell you how to debug with source artifacts, sorry. But i've heard that it should be possible.