NTSC based projects (23.976, 24fps etc.) all assume a 30 frame capture and the 24 frame timecode management is managed inside the system once captured. This is not the case if you were in a 24 frame HD project which does contain a true 24fps timecode format.
You need to go to the deck settings (depending on deck – Sony 7030, 7040) and change the timecode out to be 30fps Non Drop) If you want to go into a 23.976.fps or 29.96fps project, you will want it to be 29.97fps and non drop.
Capture as 30 then convert the timecode to 24 using the TC 24 column.
The recommended practice for NTSC based 24 frame production it to have audio timecode be 30fps/NDF. 23.976 is 29.9fps/NDF.
Michael