no eicar.comauto detection Big Sur

I successfully installed Sophos InterceptX Advanced with EDR on a new Mac OS X Big Sur install. I completed the tasks to ensure that it was installed correctly from the KB article: HOW TO: Confirm the Endpoint is Protected - Recommended Reads - Big Sur EAP - Sophos Community. However, if I download the eicar test files, they are NOT immediately detected. I have to open them or manually scan them in order to get a detection. I have downloaded the file both as .com and .zip with Safari and Chrome. Same behavior in all situations.