Able to sign successfully using ZXPSignCmdMac, but failing verification

I'm maintaining a plugin for Creative Suite, and trying to build installers for both Mac and Windows.  I'm able to use `ZXPSignCmdMac -sign ... ` and get output "Signed successfully".  The resulting .zxp files appear valid, in that I am able to build mac installers based on them that install properly and work as advertised. 

However, my attempts to sign and build windows installers are failing with "Zxp signature verification failed: 50".  In attempting to troubleshoot this, I tried running "ZXPSignCmdMac -verify" on the same files generated above that appeared to "Sign successfully", and I get: "

"Error - Failed to verify signature. Signature might have been tampered with."

I'm confused as to why signing could appear successful, when something is definitely amiss.

NOTE: I've tried ZXPSignCmd-64bit, too, with similar results.

$ bin/ZXPSignCmd-64bit -sign dist/g "foo.zxp" certs/5310dab17e8e15-SHA2.p12 `cat certs/5310dab17e8e15-SHA2.pass` -tsa http://timestamp.digicert.com
Signed successfully

$ bin/ZXPSignCmd-64bit -verify foo.zxp
Error - Failed to verify signature. Signature might have been tampered with.