Diagnosis
Upon reviewing the ESXi Host 'vmkernel' logs you are able to locate the following error message being reported at the time of rescan:
2016-04-23 22:21:43.483Z cpu13:34281087)WARNING: ScsiPath: 903: The number of paths allocated has reached the maximum: 1024. Path: vmhba2:C0:T14:L0 will not be allocated. This warning won't be repeated until some paths are removed.
Additionally, when running the following command from the ESXi Host command line interface it reports a value of '1024':
grep vmhba esxcfg-mpath -b |wc -l