[kubekniekubek]

There are way too many possibilities for why this could be happening. First, they are leading the jigeiko session so when they say it's done, it's done.

Reasons why they end abruptly... lack of time for formality and ending nicely, they see you losing form to tiredness so they end before the quality of your practice with them suffers from too much quantity, they've pushed you enough and their time is better spent with others (depending on how new you are, you will learn just as much from san dans and lower rankers and don't require the rokudans to spent as much time with you yet so they want to work with the higher ups who need more attention from people higher up), or they are simply testing you. The better you get, the harder you work, once they feel you have earned their attention, you will get the same time as everyone else. Maybe they just want to check your disposition and determination to keep doing kendo and over time they will see that and treat you differently.

Summary, you are reading too much into it. If something you perceive as rude behavior continues again and again over a matter of months or maybe even a year, then maybe they are being jerks, but I highly doubt that is the reason for their behavior. Think less, move on to next partner, jigeiko more.