Dynamic starts make the first pull faster and easier through pre-tensioning and/or a stretch-shortening reflex. This is great for heavy snatches and cleans.
 
However, the same thing that makes it help those lifts means it’s less effective at building strength in that first motion off the floor.
 
Moreover, if you’re not technically proficient to the point of leaving the floor in the same position every time, this is contributing to the problem.
 
A good solution is to generally use a static start in pull and deadlift variations—this is not only giving you much more practice of the ideal starting position and first pull posture, it’s increasing your strength in that optimal position to a greater degree.