This often stems from a poor conceptualization of the shot....which is obv a part of every preshot routine. When you visualize the shot, it should be the full shot....pot and CB position. The two lines of the balls in your mind need to make sense and 'fit'. This is actually a part of my aiming in that planning for how the CB will react off the OB helps me hit the OB in the spot it needs to be hit for the CB to do what I want. That spot needs to be a match to the spot on the OB that sends the ball in the pocket. But, if I mess up how I conceptualize the shot and the lines in my head for the two balls don't fit, a different contact with the OB is required for each, and I'm left in an either-or spot where I can pot the ball and miss the shape, or make sure of the shape at the cost of the pot.
This issue is closely related to the important 'analysis' portion of the shot routine in which we assess what happened and if it fit our expectations for how the balls would behave. If they didn't, we use that information to build a better conceptualization of the shot next time. You can work on learning ball reactions in a variety of drills like the wheelwagon drill like Bob suggested or Buddy Hall's clock drill for a set shot that allows you to see how the CB behaves when hit at 1 o'clock, 2 o'clock, etc. and remember those tracks on the table so that next time you are faced with the shot you will at least conceptualize it correctly and match up tip position with the intended paths of both the OB and CB.
As your conceptualization of shots gets better and the lines match up more, you will find yourself in fewer either-or spots where you are left to choose between focusing on the pot and missing position or focusing on position and missing the pot. It is as much a game knowledge thing as it is a focus thing.