Do your doors have a bunch of interior upholstery stuff on them. If so, this is probably at least part of the problem. The newton rating of the gas struts was not spec.ed for a bunch of wieght added to the door. You may have to get higher rated struts
Both Ron Grover and I have our doors fully upholstered. I agree that is probably adding to our problem and why we both ordered the stonger struts that Ron found. I actually replaced the struts once with the ones from Van's but the problem just reoccured after awhile. After that door hits you in the head a couple of times you finally say OK that's enough of that
I actually haven't received mine yet. They come from Germany and take around 4 to 6 weeks to arrive after the order is placed