It seems there was definitely some drama between Aaron Rodgers and Mike McCarthy
www.cbssports.com
The story also states that Rodgers got tired of seeing his receivers run the same routes all the time, which only happened because McCarthy refused to change his offense. To fix things, Rodgers apparently decided to start changing the plays that McCarthy was calling on the field, which happened nearly one-third of the time.
Basically, things got so bad that receivers weren't sure if they should run the routes that McCarthy had called or if they should run the routes that Rodgers had called. That led to an ugly situation in November involving Equanimeous St. Brown.