The electric handbrake on the mk 4 can be quite sensitive to how slowly and carefully the handbrake is applied.
Can you explain further? I thought you just toggled an electrical switch and it came on of its own volition?
It comes on automatically if you have it in 'brake hold' mode . The brakes are held on at the same pressure you used to brake to a complete stop. But if you toggle the electrical switch yourself its best to wait a second or two until the car has settled down on its springs. . Difficult to explain but when you apply the electric handbrake the power braking action tends to induce the rear of the car to rise slightly. So slight you dont normally notice. But if it happens at the same time as the car is naturally settling on its springs the two actions may conflict, and there may be a slight lurch or groan. I may have got the forces involved the wrong way round but the result is noticeable for me , but very slight.
What you definitely want to avoid with electric handbrake is applying it very slightly before you come to a complete stop (a bad habit I had acquired.
) If you do the braking action is so powerful you really lurch to a stop.