ISE 2.3 Patch 5 has been released at ISE 2.3.0 Software Download since 2018-Sep-17, with the filename ise-patchbundle-2.3.0.298-Patch5-18082702.SPA.x86_64.tar.gz.
For more info, please read Resolved Caveats in Cisco ISE Version 2.3.0.298—Cumulative Patch 5.
PS: If you have an inquiry on a specific defect or a general issue on this patch, please start a discussion at http://cs.co/ise-community