Miscellaneous: Assist doesn't show proper HP level

[USMikeC117]

Zones: So far, UGuk, Unrest, Highpass, generally everywhere I've leveled recently. Doesn't seem to be limited by zone.

Problem: Some times when using the /assist command, my target's HP will stay locked at 100%. I'm seeing him take damage from group mates. If I nuke, his health will still show 100%. Without retargeting him, the window will show 100% until the mob is dead. Can't seem to find a definite way to replicate, seems more random than anything else. Minor bug, irritating more than anything else.