poptopclk

I had an issue that APPEARED to be a bad strut. Xentry couldn't raise it or lower it, all the other 3 corners worked normally.
I ended up replacing it and the SAME problem still remained !
I then replaced to Valve Block and the issue was resolved.
The take-away, replace the VALVE BLOCK 1st it is cheaper & easier than a strut replacement.

Panzerknacker

If it was not sagging over time then I would not assume a leaking spring.