Webkit Content Crashing?

Running Safari Version 13.1 (14609.1.20.111.8) on macOS 10.14.6 (18G5006)

Seeing this in Console after reboot:

com.apple.xpc.launchd[1] (com.apple.xpc.launchd.user.domain.501.100011.Aqua): Caller not allowed to perform action: com.apple.WebKi.13975, action = pid-local registration, code = 1: Operation not permitted, uid = 501, euid = 501, gid = 20, egid = 20, asid = 100011

Then this after starting Safari:

com.apple.xpc.launchd[1] (com.apple.WebKit.WebContent.9E4BB5E7-91F8-4112-82DB-E75387E5DF8D[1137]): Service exited due to SIGABRT

Only installed latest macOS Beta / Security update for 10.14

Safari refuses to load any pages and the Top Sites tab shows blank pages.

All pages load with "A problem was encountered loading this content..."