Is it possible that the LVS PUSH DEVICES SEPARATE PROPERTIES statement is present in some file that is used with an INCLUDE statement in the main rule file?
Are you submitting the job with a batch command, or are you using Calibre Interactive GUI to submit the job?
I did check many files under the foundry's calibre directory, including drc, lvs and xrc rule files as well as the files that are bundled together with xrc rule file for xrc extraction. I couldn't figure out where those lvs push devices separate properties is defined.
I use calibre GUI.
I checked my LVS GUI (the setting initially is very important during the connectivity extraction phase of LVS) but I didn't see an option for it there. Maybe somebody with PEX experience, or someone familiar with your foundry setup will be able to join in the discussion.
You didn't mention which version, but the GUI has been stable for the last several releases so maybe this information I found in the latest version will help.
According to the Calibre Interactive manual, there is an option "Keep parasitic net models marked with _noxref from netlists". The default is enabled, or allowing them into the netlists. (Sounds backwards to me, but that is what the manual says.) If you disable this GUI option, _noxref nets are suppressed from the netlist.
The page shows the path to the option as Options > Netlist > Reduction and CC. In the 2011.4 version of the manual, it is in the "Setting PEX Options" section.
Hope this helps-