Yes it is common. The plastic is quite frail and will mark, scuff and rip when it comes into contact with almost any hard surface - and this includes the other spring/stilt!
Do a search for spring covers or just cover it in a few layers of electrical tape and this should be adequate enough to stop any damage going through to the actual spring. It wont effect the springs performance in anyway so if you are unsure whether you have enough tape layers on it then the answer is no