This issue is resolved in ESXi 6.5 Patch Release ESXi650-201811002, available at
VMware Patch Downloads. For more information on downloading patch, see
How to download patches in Customer Connect (1021623).
Workaround:
To workaround this issue if you do not want to upgrade, create DRS rules to separate virtual machines to make sure they either run on ESXi 6.0 hosts or ESXi 6.5 hosts in a Cluster with mixed ESXi versions