One way to correct this technical problem is to work on keeping the lead wrist firm but quite often this focus is to the detriment of feel.
Another way which is more constructive in addressing the problem would be to try and get the hands and clubhead to move through the impact area at a similar speed which maintains the correct wrist position without sacrificing feel.

A lead wrist that breaks down when putting is a cause for many poor putts, you often find the ball will go left off the clubface (right handed golfers) plus it is very difficult to control distance with this particular action.

Another way which is more constructive in addressing the problem would be to try and get the hands and clubhead to move through the impact area at a similar speed which maintains the correct wrist position without sacrificing feel.
GOLF TIP COURTESY OF KENAKO GOLF & SPORT ACADEMY