I've seen that twice before. I have no logical information as to why it does it, but I solved both of them.
Simply disconnect the battery overnight - by morning the memory has totally cleared. The computer reverts back to it's default values.
Then the first few minutes of driving it, drive it fast and slow, do not "take it easy on it." The computer has to re-learn everything, so let it experience all kinds of driving conditions.
It takes a long period of disconnect, like overnight, to get "ALL" the old memory gone. It doesn't work to do it for a short time. Force clearing with a scanner doesn't help either. (Yes, I tried both ways.)
My only thought is it must get some kind of interference loaded into the memory, clearing it and starting over worked both times.
It could have been a lightening storm, radio station, or some outside electrical interference caused it. It's also possible a low battery or bad battery cable connection, or something sparking, may have caused the electrical interference.
Let us know.