ASM (AWAF) should not be set up with everything on and in blocking. That's not how it works. With ASM, you want to develop a policy before putting it in blocking mode, if you can. The easiest way to do that is to develop a policy "in QA,' by sending ONLY good traffic at the VIP with the policy. Once you've sent a QA run at it, AWAF can learn all as good / expected traffic. At that point, you can put the policy in blocking mode on your production VIP.
The trickiest bit with Sharepoint is the dynamic URIs. I think there may be a pre-built policy for Sharepoint, if I'm not mistaken. What version are you on?