Unfortunately, this happens very often when they are moved and almost always when shipped.
If you do a search on the fora, you will find more info but it's basically
a matter of the woofer magnets glue losening, allowing the magnets to
shift to one side through their own magnetic force, sandwiching the coil
against the center piece. This freezes the cone completely and you can feel the difference
if you - very gently - push the cone inwards with a finger (a couple of millimeters will
be enough, no more!). The cone should move easily and spring back when you let go.
Not an easy fix, I'm afraid, but there may be some pro refoam'ers capable.
Reconelab maybe.
The same problem is seen in the Beovox S45 and S45.2 woofers as well as
the Beovox M70 Filler unit, the latter being a very similar build to the P45 woofers.
I recommend all owners of the above speakers to place a bead of
2-comp. epoxy glue (araldite) around the magnets, where it meets with the
metal basket (speaker chassis).
Martin