I have enabled WAF policy and apply to a Virtual server in Transparent mode. When the user execute JSON script in Postman tool, they are thrown a support id.
Is it an expected behavior from WAF ?
enabling WAF may block requests if you don't custom your policy according to your needs.
if your json content has some special characters or any pattern that may match a signature, the request may get blocked.
you can look at the logs and see what is the reason of the blocking.