Apparently this issue is now being worked on, according to the current newest post in the "Fixed" Bug Reports forum, which can be viewed in full here, though I will add just "The Hunt" notes in this post:

Quote Originally Posted by NOC_EU
The following adjustments have been made to “The Hunt”:
- Elite marks maximum HP has been increased.
Rank B maximum HP has been raised from solo to light party level, Rank A maximum HP has been raised from light party to full party level.
Although the Rank S maximum HP level was already intended for multiple parties, we have further raised the necessary number to require even more parties.
Similar to Odin and Behemoth, because raising the maximum HP of Rank S means stressed server loads due to the concentration of players, we plan to make ongoing adjustments as we watch the server situation.
- As the elite marks HP is increased, the amount of contribution points in which affects the reward after defeating will be eased.
- S rank elite marks will have top display priority.
Because the elite marks maximum HP have been changed to reflect the party numbers required, we are also looking into adjusting the amount from the “Regular mark bills” and “Elite mark bills” reward. We will continue to make careful content adjustments as we monitor player trends and server stress loads.
I'm glad that the Dev team is beginning to, in a roundabout way, acknowledge this issue; however "The Hunt" was only part of a larger problem. Large scale FATEs, World Bosses, Seasonal Events, and other such largely populated world events will still be plagued by entity disappearance if the rendering issues are not looked at more closely than this.

Also I feel a bit offended that when I, and others, brought the issue to light in the Bug Reporting forum the case was closed and filed under "Not a Bug". Now suddenly a fix relating to my report is implemented and filed in the Bug Reporting forum under "Fixed". So it's not a bug when the players report it but IS a bug once it's fixed?

I understand that the team has their fair share of things to worry about, and perhaps the ruling on my report was simply made before additional reports came in. Though still I feel as though it would have been more professional to have at least investigated the issue some before simply tossing it aside a few hours later. I'm just not sure how the dev team can expect the playerbase to feel comfortable using the Bug Reporting or Technical Support forums to assist them when reports are brushed aside like this, seemingly just to save face.