Our 2004 Designer 5er doesn't have any issues like you describe that I've noticed on any of our 3 slides, but I will sure double check next time I have a chance. I agree that yours could be the result of leaving the slide out for a long period of time - ours has never been stored that way.
2003 Ford F-350 V-10 Crew Cab 4WD Long Bed
2004 Jayco Designer Medallion 29 RLTS 5th wheel
Bill, Gayle, and Mindi (dachshund)
Retired at last !
Nothing is foolproof to a sufficiently talented fool.