Anyone with experience deploying ASM in blocking mode for a product called Powerschool?

This appears to be education-sector-specific product, I am guessing most people on this forum(like myself) come from the business side, so unable to help directly.

You need to understand the application's technology, so you could map it to correct attack signatures, e.g. is it a .NET application, a Java application, a PHP application? What kind of auto-learnt things are throwing false positives? Attack signatures? Parameters? URLs? HTTP protocol compliance? Has this product been penetration-tested, do you have a pen-test report or a list of known security vulnerabilities?