I'd guess air. 2 yrs later and I still have air in the system. I've read its supposed to purge out through the pump when it runs but it doesn't.

Its not that big of a problem if one side lands on the header first. It easy to just reach up and pull it down a little to get the hook into place. I do it all the time.

Is the frame different from a manual to power top?? I have only had the power top. For the couple of times a year I move it I could have a manual top, it wouldn't matter. I put it down in the summer and up for winter storage. And maybe a time or two on between if its cold out or if rain sneaks up on me.