Can a framing sentence sound memorised to the examiner?
Repetition is the giveaway, not the wording. Keep two frames per shape and change the second clause to fit the question.
It can, and the giveaway is repetition rather than the words themselves. A frame that arrives identically three times in one discussion sounds like a script; the same frame with a different noun, or with the position changed, sounds like a habit. Keep two frames per shape and vary the second clause to fit the question, since nothing in the band descriptors penalises preparation, while hesitation that searches for language is what the fluency criterion describes.
One test tells you whether a frame has become a script: answer the same question twice in a fortnight and record both attempts. If the second recording uses identical wording and an identical reason, replace the frame instead of rehearsing it harder.