Vector 3 Power Imbalance

I am riding on a trainer right now

I have a Garmin Forerunner 945 as my main recording tool (I do not have a head unit and trying to avoid buying one until next spring when I can get outdoors again)

I manage my Vector 3 (just go them a week ago) from my iPhone and currently running firmware version 3.80

I have tried the standard rotate the pedals till they wake up and leave them in the horizontal position so they can auto offset (I have this turned on).  I also leave them in this position when I'm done with my ride.

I have done two rides (45 min, 1 hour) at a pace to keep my heart rate low.  Since i'm a novice this means my power is ~125W and my speed between 18-20MPH.

Problem is my power balance is very Imbalanced.  My concern is I don't know if this is "real" or something is off with the pedals.    If it is real, I can at least work with somebody to correct this.  Personally I did not buy the power meters to measure my power.  I got them to give me feedback on my technique to make sure i'm not developing less than ideal habits.  

So...is there anything I can do to begin to figure out if the meters are right or is it me?