Happened to me in my nidan test - jo-dori...... er... now what... er... OK, uke hasn't countered me yet so I'll try this... Whew...
One think I can suggest - Whether you're trying to unlearn something or learn something new, take some time, quiet time, at home, and practice some part of what you're trying to "get" - maybe 400 or 500 times, slowly - accurately - daily - for a week. I had to relearn tenkan early on, and later, and later still.
In some training communities, people say slow is smooth, smooth is fast - start slowly, blend out the "stops" so you can go through the movement without "checks", and gradually speed up.
When you don't have to think about what's coming next in your movement, because it's a trained response, then you can get stuck being predictable, but if you're not thinking about what your body is doing, you can be more "in the moment" and respond more freely to the movements of the "attacker" because you're not paying attention to whether or not your knee is in line with your toes, or if your arms are in front of you...
That still happens so far on? I suppose under the pressure of testing - we don't do tests at my dojo until 1st kyu so I haven't had to deal with that yet.
You make a great point about at home practice, though unfortunately many of the things I need to work on either need to be guided by someone more experienced - who knows what I'm doing wrong and how to correct - or are not so easily done at home safely (like ukemi). But I think with patience and persistence I can get there eventually, this is just the first "step back" as it were as I have been doing - I think - rather well up until this point and had much praise from various sempai. What was mentioned earlier about ego sneaking up was a good point, it does indeed set you up for a fall in the end when things get hard.
One of the things I am trying to work on is fluidity as you mentioned, at least at first it is very first movement, irimi tenkan, next movement, step back, third movement move arms/hands, fourth movement move forward. Speed has been a hurdle, I love fast techniques so often I find myself "rushing" and it makes me careless, I sacrifice my balance/position/flow to perform in a way that gives a great rush when it works - and comes off awkward and jarring when it doesn't. So slowing down, trying to work on making everything flow together, is something I try to remind myself of from time to time.
Your final point is well noted, in time this will be something I will have to be careful on, but for the time being as you mentioned, my concerns are of a more basal nature
. I think this is where there was some disagreement earlier, it is not that I reject the idea of "freeing my mind" so to speak and don't want to - just that right now, I can't, because I am frankly not good enough yet.
P.S. To the kind observer that PM'd me, thank you for your encouragement! Your Inbox is full so I could not respond to you in private