HOWEVER, someone there helped me discover that the issue is only with pistons created in the Hubitat version of WebCore. If they're created in a SmartThings version of WebCore and the imported into Hubitat's, they work. I've found the same thing.
Anyone know if this is a bug? And if so, who I contact to make aware?
I don't know the answer to your question but having JUST transitioned from smartthings webcore to HE webcore, I have noticed multiple differences in the versions so what you're reporting definitely isn't impossible. I too would like to know whom to report these types of bugs.
Forgive my ignorance (still fairly new to HE) - Are you referring to the Hubitat firmware or Webcore? And assuming I am on the latest, how do I revert to an older version?