Check the dev console ignoring the resource cache when loading pages,all network requests status are 200. Verified this bug. 4.2.0-0.nightly-2019-11-28-230858->4.2.0-0.nightly-2019-11-28-180854 Safari Version 11.0.3
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2019:4093