If you're seeing strobing effects with motion blur in your Gelato images, you probably have the temporal sampling set too low. Sampling with Gelato is very inexpensive relative to other renderers and you can usually crank up the number of samples without experiencing a significant performance hit.
Fast-moving objects will appear to strobe, or break up into several "stamped out" images, if the number of time samples is not high enough for the amount of motion blur. When this happens, you should increase the "temporalquality".
In Maya/Mango you can do this by going to Render Settings/Gelato/Motion Blur.