Add on's jumping on taxiway in FS9

Does anyone besides me have an issue ongoing with add on aircraft in FS9
that involves the following? I'm having it now with one company's add on's
only. I'd like to know if it's a sim related issue or just something from
this company's aircraft.
After a landing and while taxiing, if the view is cycled through VC, spot,
and tower, when the tower view comes up, the aircraft drops suddenly about
two feet to the runway, the gear smokes and the struts compress. It's as
though the aircraft was literally dropped to the ground from two feet up. It
happens every time after a landing. If you cycle the views when moving, you
get tire smoke as the mains contact, if standing, just the drop and strut
compression. The defaults don't do this at all.
If it's a known issue, can something be done to fix it?
Many thanks,
Dudley