Personally, I have never encountered damaged o-rings.
When leakage occurs, it is mostly because the intended outlet path of water/coffee is blocked:
Either the holes in the pyramid plate are clogged, or the actual coffee outlet port is clogged with dried coffee remains.
The water then simply seeks another way out ;-)
The dried coffee remains can also lead to bad sealing contact areas where the rim of the coffee pod is pressed against.
Only recently, I have encountered several Citiz machines, where the water leakage came from a (hairline) crack at the topside of the brewing unit.
To be more precise, the crack was on the top of the part which has the three teeth in it. It is barely visible to the naked eye...