A correct kettlebell grip is one of the main things to focus on when you start kettlebell training. You have to get it right, take some time away from everyone and get yourself a light kettlebell, play with it, move it around till you find the two or three points in racking where the weight should rest.
It’s called “broken wrist” when your wrist is not straight/neutral in racking or overhead position, all the weight is pulling down on your wrist. Most people employ this grip because they might feel less pressure on the forearm, however, one should take the time to find the right resting points to maintain a neutral wrist. The resting points are; around the heel of the palm; on the forearm; and against the biceps when in cradle racking position.
The second cause for an incorrect grip/insert is a tight grip and not opening up during the clean for a proper hand insert.