Yes contact the shipper/ vendor.

It is possible that it was not glued as well
as it might. If I was making one I would
support it from below cover both sides with
foil or plastic wrap and stack some books
and bricks on it after gluing.

This should work on a paddle strop built
on a solid chunk of wood but not one built
in the style of a loom strop with an air gap
in the middle. I would be tempted to dry
this if you have the strop I am looking
at on the web.

Leather is interesting stuff. I had a wide strop
that developed a bow partly because it
was not supported by a canvas back strop and
partly because I applied way too much strop
dressing one time.

I took it to the kitchen and saddle soaped the
heck out of both sides two days in a row. Then
I hung it out to dry for a couple days, applied a thin bit of
mink oil then a thin bit of strop dressing from
my 40 year old first buy jar and it was good as new.
It was a bit stiff at first but it came back nicely.