Good data: I found this link and summary somewhat reassuring.
http://members.iinet.net.au/~fotoplot/invicta/invicta.html
Summary The "Hesitating Second Hand", observed on Invicta and other brands of watches is simply a characteristic of the "Indirect Seconds" type of movement design and in no way has any effect on the watch accuracy or timekeeping. If any watch company wanted to do something about it, the simplest, and really the only practical solution, would be to poise the second-hand. However, tens of millions of Indirect Seconds type watches of many different manufacture, in all grades from the cheapest pin pallet to high grade Swiss watches have been made in the past 50 years or so, and have been used with no problems at all. Indeed, it is hard to imagine how this characteristic could ever be observed during normal wear on the wrist, anyway. One can only assume it was claimed as a problem in an attempt to find fault in a watch which offers such excellent value for money as the Invictas do. So all you owners of Invictas, Omegas or any of the many, many other brands that use the same method for driving the second hand, there's no need to worry about it!
and this --if you don't know what you are doing
Increasing the tension of the brake spring must be done with great care, as too much tension will start to significantly affect the balance amplitude (from the extra friction in the train), and thus the timekeeping.