Common issue with chronographs, it can have several causes.
Most commonly it will have too much wear and build up dirt in the chronograph mechanism, this will create too much friction to overcome especially when it has to push the minute wheel near the 1min mark.
Another thing you see frequently is that someone who doesn't know what he's doing adjusted it, meaning that the chronograph driving wheel might engage too deep or too shallow, or the minute counter jumper is bent or adjusted badly.
Hard to tell what is going on exactly without opening it up and checking it. It could very well just be time for a service
