I’m showing the same flaw as Elijah indicates:
Source footage is 23.98 on a self contained MOV file with QT metadata timecode.
Take that footage into Compressor and use the Timecode overlay and the resulting file with the TC burn-in does not match the timecode embedded in the original source file.
For example:
First Frame of Source file: 12:38:05:11
First Frame as represented by the Burn-In from compressor: 12:38:51:00
WTF?