Hunt mobs disappearing during combat (culling issues)

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Date & Time: 7/13/2019 from 10 to 11 AM central time for the A train
Frequency: any time an A train is occurring
World name: Any Primal world (Famfrit and Hyperion for most of the A trains)
Character name: Brizzyne Windsong
Retainer name: NA
NPC name: NA
Monster name: All the Shadowbringer A ranks (see it some with the S ranks)
Class/Level: Bard 80
Party or solo: Party
In-game time: Various
Area and coordinates: All zones
Housing: NA
Steps:
1. Get a large group together to kill A or S hunts
2. Start combat with the hunt
3. Hunt will randomly disappear from view
*Add more steps if necessary

Connection Specs
- Type of internet connection/provider: wired /
- Modem maker/model number:

(All the players in the area are reporting the same issue with the hunt mobs phasing in and out of view during and even before the fight begins.)