Hi, You can go to Transmittal Set Details dialog box for the current Transmittal Set, the'Create New Revision in all Included Layouts' is always checked for a project's first Transmittal Set. This will assign a new revision ID for every layout you've...

This might be a long shot but have you checked the element's Renovation Filter Status? 'Override' must have been selected in one of the filters as you've mentioned this is coming from an existing base pln.