Have a good look over the shock to see if you can ID the Why .................... If the ones on one side have failed then it could be bump stops are shot, a shockie will fail if they often go to full compression or full extenstion, mostly over compression due to bump stops flogged out or wrong size shock fitted, check the shockie mounts that they are in line, also that the swinging arm bushes are in good shape, if the shock is not operating inline the shaft will wear the seal eventually.....
Measure the shocks to make sure the extension and compression distance is greater than the swinging arm movement, don't assume the manufacturer got it right with parts.