Bug creating a 1 minute comp in 29.97 DF

The Current Time Indicator will always be placed at the start of a frame. If your comp is 30 seconds and 24 fps, then the CTI will stop at 0:00:29:23. If the 30-second comp is 29.97 fps, then the start of the last frame is 0;00;29;29. If the comp were 120fps, the start of the last frame would be 0:00:29:119.

The last frame has not been played yet, so the time indicator shows the start of the last frame. If you move the time indicator to the end of the last frame, so it is stopped after the composition has played, then the time will be exactly 0;00;30;00 if you use drop frame timecode. Non-Drop timecode uses a colon (:). No frames are actually dropped with DF timecode. Only frame numbers are dropped every few seconds so that the actual hours, minutes, and seconds remain accurate. That nonsense happened with NTSC television (60Hz) added color, and they didn't have enough scale lines for the color information, so they slowed the frame rate from 30 fps to 29.97 to add the color info to the interlaced signal. 29.97 is still the broadcast standard for all NTSC countries. That's any country that has 60Hz power. 

There is no error. There is no bug. The CTI is just stopping one frame before the end of the comp so you can see what is on that frame instead of just looking at black. That's the way all compositing apps work. Editing apps like Premiere Pro show black when you trim a clip to the CTI. That is also standard because when you are editing, you want to see the frame you are cutting off, and in a compositing or animation app, you want to see what is on the last frame to ensure it is good.  I hope that makes sense.