"Anonymous. To save starting another bit of writting. Foxtrot step three has no CBM."
Nobody said it did!
"The third step if the Natural is coming after a half a turn over steps 1-3 cannot be compared to the Reverse Turn."
Sure it can. It's not an exact mirror image, but there are qualities that are mirrored between the two. Notably the quality you overlooked in this case: in both figures, the body will be underturned at the step 2- step 3 transition, meaning that the third step (to go direclty down LOD) would have to fall somewhat across the body, which is not actually rotated to back LOD. But of course that does not mean the third step is in CBMP.
This is an example of a step which falls across the body, BUT NOT ACROSS THE STANDING FOOT, and thus is not in CBMP.
"If you are following the book the Natural Turn starts facing the LOD."
Yes, but it's much more commonly danced in accordance with the note directly underneath the chart, which tells you how to commence it DW.
"The third step is still straight. I am looking at the chart now. The step is as straight as a bullet in both cases"
Yes, the step is straight, but the body is not yet pointed in the direction of the step, hence the step is somewhat across the body. But not across the foot, so not in CBMP.