I think I found the answer I Harman's AIR SDK Release notes for build 176: "Gamua-287: Installer on MacOS now copes with iPhone XR and the newer UDID format"
So the UDID format change appears to have broken the ADT installer. We'll be upgrading our SDK from build 33.1.1.86 to latest build 33.1.1.217 soon and see if that fixes it for us.
