Daily use here, about 2.5 weekly 20x limits, never got flagged for code topics including finding memory safety vulnerabilities in my C++ project, but just got flagged for the first time for biology-related topics because I asked it to implement crop genetics and cross breeding into my game. Was able to bypass it by having opus reword the prompt (gene -> trait, cross breed -> trait mixing), and, critically, insisted that it not use any biology related words in its thinking or responses.