How to stop using the previously been evaluated pipelines

Greetings,

I am working to benchmark TPOT. So, I may run tpot multiple time for the same dataset. When I do this, I see this message:

"Pipeline encountered that has previously been evaluated during the optimization process. Using the score from the previous evaluation.
Pipeline encountered that has previously been evaluated during the optimization process. Using the score from the previous evaluation."

I do not want tpot get advantages from the previous trials so I kept the flag of memory=False. I have also deleted tpot_pipelines folder in every run but I still see the same message.
Waiting for your response
Thanks in advance.