Does the sentence make sense? Doesn't it have to be corrected like this?
kk206)The matter must wait pending her return from the U.S.A
=> The matter must wait pending before her return from the U.S.A
Nope. Your proposed correction is incorrect.
"The matter must wait, pending her return from the U.S.A." is correct but perhaps slightly unnatural.
More natural would be:
The matter must be postponed until her return from ... or
The matter must await her return ... or
The matter cannot be dealt with until her return ...