The ArcGIS Server Security 2018 Update 1 Patch has been re-released with a ‘B’ setup to the support site. The URL is:
Important note August 16, 2018: The 10.5.1 version of this patch was updated to fix a regression that impacted the ability to visualize data from the spatiotemporal big data store. Users are encouraged to download and install the updated patch to correct this problem. None of the security fixes included in the original version of the patch were impacted.