The process I would use to determine what the problem is would be as follows:

1. In the morning engage the autosteer on the AB line you created. Drive relatively slowly and stop when you're sure that you are very close to centered on the line. Mark the center of your tractor on the ground somehow (a little flag would be my choice but whatever works is fine)

2. Get centered up on the next line over and do the same thing while you're even with the first mark. Measure the distance between the two marks. If it is 12', there may be some problems associated with the implement. If the distance is not 12', it's likely is something wrong with the manner in which the Mojo is set up.

This will help you determine whether you're dealing with an implement issure or a Mojo issue. Once that's been determined, progress in resolving this issue should be rapid.

I would imagine that you know your implement pretty well so I doubt that's an issue. I know nothing about the implement you're referring to but I do know that with some equipment the manufacturer will say that it's on a certain spacing when the reality is that for various reasons they can't make that work for every section. An example would be our air drill. It was supposed to be on 7.5" spacing but a few rows had more spacing than that because they were near flex points and they would have hit up against other row units had they actually been on 7.5" spacing. Anyways, my point is, if the Mojo is actually driving 12' swaths, you need to start taking measurements on your implement to see what it actually is rather than what the manufacturer said it is. Another thing to concider is the implement offset that you said you do not have. While I don't believe this would account for the large problems you're describing, when you're talking RTK level accuracy, it's entirely possible that implement offset may be more significant than you think due to the possibility of it pulling slightly sideways. Machinery usually isn't built perfectly. One way to measure this (assuming the antennas on your Mojo are centered on the tractor and your drawbar is centered on your tractor) is to drag a chain from the drawbar and measure from the chain to either side of the implement while you're stopped in the field. If these two measurements are not equal, then the implement is not pulling perfectly straight which could corrected for by using the implement offset.

If the Mojo is not guiding you on 12' swaths, consider the antenna mounting first. The red antenna should be on the right side. The other should be on the left side. They should be an equal distance from the centerline of the tractor. As I'm sure you've read, these aspects are very important to making it work properly. As an example, maybe the red antenna is 20" to the right of the centerline of the tractor. The other one must be 20" to the left of the centerline of the tractor. If the antennas are mounted properlly, then software configuration must be analyzed.