I guess, with the transition of Karate, and learning the basic movements of Aikido, over and over and over and over, until my brain finally gave up and remembered, is the hardest thing to do.
Most people have read books by John Stevens Sensei, and some have gotten the chance to attend a seminar with him. About three years ago, at my firt Stevens seminar, there were no less than two hundred people, at least a third teachers of various black belt levels. With in that group who were following the jo and bokken warm ups that Stevens sensei goes through, about a quarter of them got lost at various points when we would do other than normal dojo exercises. From the four points, to the eight points, then reverse the clockwise motion to counter clock wise.
There is nothing so funny as seeing a teacher who is the hero of his/her dojo get lost while funny looking white belt falls into motions within one completion of each new exercise. Maybe it is mimic training of marching in the service, or MA training of follow the leader in warmup exercises, but weapons always seems to come easy to me.
My point being, that no matter how long you mess up, or get frustrated, somewhere, sometime, somehow your brain will sort out the mystery and get your body to go along. Even teachers get frustrated, but laughter is the best medicine for that.
It took many, many months of Aikido to break me of my bad habits of making novices use more force than needed, or getting both sides of my body to work in unison ... you know, left hand with left foot, right hand with right foot. But, slowly, surely it happens ... just like another birthday every year, one day, there it is.
Many people do not talk about the changes the body goes through as it gets older, but maybe your training is being held up because your body is not what it was last month or last year? Don't get ahead of yourself by trying to do advanced techniques beyond what you can do that day. Sometimes reviewing the simpler, easier techniques actually increases your advancement in training.
I know in karate we were taught to do Kata forwards, backwards, and on both the left and the right side ... not always the mainstream, but done slow, with effort and forsight to attackers in kata, then many things you thought you knew become new again.
I would say, if difficulty persists, watch from the sidelines, and see if it appears different than when you are training? A notebook might be helpful for finding things you have missed ... I know many of the classes I have had to watch because the room was spinning from my own illness, have been sometimes more insightful than training?
Hope you get past this little problem, good luck!!