I can confirm a variation of this bug over here.
Looks like it's also affected by changing the bar 1 position in the Synchronization settings. For example, if I'm working on a cue in the middle of a movie, I will set the Bar 1 position to the timecode of that cue.
In that case, entering the timecode into the transport bar gets completely out of whack.
For instance...
1. Set frame rate to 23.976 to match my movie.
2. My movie starts with timecode 00:59:58:00, so in "Movie" preferences, set "Movie Start" to 00:59:58:00.
3. Cue starts at 01:26:51:02, so set Bar 1 position to that timecode in Synchronization settings.
4. Enter any timecode in the transport bar. For example, 01:30:00:00. When I hit Enter, Logic jumps to 01:54:38;02.
This is a total deal-breaker, since I have to manually scrub to get to the timecode location I need. Filed a bug with Apple.