We have had reports of two Apple rejections today for Titanium apps submitted for clients using an older 2.0 CI build and 1.8.2. The rejection is based on the use of deprecated UDID property. Was confirmed by a Titanium developer with at least one other native dev who got rejected:
This seems to be a very recent occurrence, so little data is available at this time. This will require investigation and validation, along with a measured approach at dealing with moving totally over to the new UDID generation mechanism.