How often do U.S. consular officers rotate from one embassy to another one?

Question

what are the chances to be reinterviewed by a different consular officer on the second interview past six months from the first one at the same embassy (american K-1 visa interview)

Answer 1

As noted above, there are too many variable at play.  It seems you are alluding to "visa shopping" - trying to manipulate the circumstances in order to maximize the potential for getting a more favorable outcome.  It does not matter which officer interviews you - the decisions are dispassionately based on the documents submitted and the information your provided at the time of  your interview (which are included in the permanent case file notes for future officers to see).

Answer 2

It varies considerably. Not only do consular officers rotate from one embassy to another, they can also rotate between positions within the consular section, or to other positions outside the consular section within the same embassy.

Answer 3

Yes, building on the prior response - while it is entirely likely you'll be interviewed by another officer, you are also highly likely they have taken notes and noted their decision in your file.