Current State of Corps Breakdown/Recombining?

[Paracelsus57]

After experimenting with corps breakdown to ship units overseas, I have discovered some odd game behavior. For reference, I have the "Unlimited Breakdown" option ON.

The Japanese have experienced no problems, either with breakdown, or with recombining, notwithstanding that I chose none of their breakdown divisions as MOT.

The Italians have had more troubles. The MAR I broke down into MAR and INF respectively, and they recombined right back. The Alpini I broke down into MTN and INF, and they refuse to recombine. A generic Italian MOT I broke down into MOT and INF, and they also refuse to recombine.

Some searches online revealed rule 22.4, which would seem to explain the Alpini disaster, but not the Japanese success, nor the good experience with the Italian MAR. Is there no way to recombine MOT corps?

For future reference, what really SHOULD be happening?

Notwithstanding that, how do I salvage the Alpini in my current game? If I delete both daughter DIVs, can I build the corps again?