"Customers deployed on the new FL2 proxy engine, observed HTTP 5xx errors. Customers on our old proxy engine, known as FL, did not see errors, but bot scores were not generated correctly, resulting in all traffic receiving a bot score of zero."

This simply means, the exception handling quality of your new FL2 is non-existent and is not at par / code logic wise similar to FL.

I hope it was not because of AI driven efficiency gains.