The security scheme of TOTP states that the secret is a long-term shared secret. The scheme doesn't make any assumption about validity of tokens in cases which are simply not foreseen by the specification. So you are asking for something which is completely outside the scope of what the TOTP concept addresses.
It's like asking "if inc on paper was invisible, how would we read?" and the answer is: Inc is not invisible, for a very good purpose.
Maybe you want to ask something different like "how can we make this more secure by changing the long-term shared secret to something more dynamic". If so, please rephrase the question.