Same happens for a local admin with RO permissions. Seems to be a UI loophole.
I will ping Support and let them know it happens to SAML and non SAML admins along with a quick video showing exactly how it's accessible.
To confirm the way you're accessing it is going to a switch, clicking on a port, then down in the tools section clicking the packet capture link yes? Also, it only applies to the new version page. The old version doesn't appear to show the pcap link.