I just received my shock/strut set and upon first opening the rear shocks I found that the first one didn't seem to extend back out after being fully compressed. I pulled it outward a little and it then began moving rather slowly, taking a minute or more to fully extend. The other shock is similar. Could they both be bad, or is this something inherent to these shocks? I've always judged shocks being good or bad (upon receiving them) by testing whether or not they rebound quickly.