Convert 1080p/23 to 1080i/59 - DX LTC out will not make Dropframe TC

If I open a 1080p 23.976 project and set my Digital Cut Output Format to 1080i 59.94 / NTSC, the LTC output from my Nitris DX chassis is always Non-Drop timecode, even when set to Drop Frame. The RS-422 setting will control a Drop Frame deck OK but we don't use much tape any more. I would like to use the LTC output to trigger a file encoder but we only use DF timecode. I have two of the same Sy6.5.3 DX systems that both act the same.

Has anyone else tried this?

Thanks