Platform: Windows 10
ISP: Telenor
Type of Internet Connection: Fiber
Internet Connection Speed: 300mbps
Date & Time: Mar. 14, 2021 1600 CET
Frequency: Once (did not reproduce)
Character Name: Harribel
Race: Hume
World: Bahamut
Main Job: Paladin, Lv.99
Support Job: Blue Mage
Area and Coordinates: Odyssey Sheol C, Floor #2
Party or Solo: Party with 5 members
NPC Name: None
Monster Name: Draugr + Scorpions
Steps:

We entered Sheol C to farm Mog. Segments for use in Sheol Gaol, and proceeded to floor #2 via the transcendental radiance.
On floor 2 we buffed ourselves up and prepared to pull mobs.
The paladin then pulled 10~ monsters and positioned them in a nearby alcove, to tank and hold hate from the front.
During this time, the R (Received) value for most players in europe attending the instance, was 2600-2980~ reaching the limit of the games transfer potential.

Because of this heavy network latency, the game did not function correctly, spellcasts were hard to time and difficult to confirm if they happened, as the combat log and the visual display is affected when suffering from so much network latency.

The effect was extremely similar to the issues experienced previously in Odyssey Gaol; and the group immediately tried the same composition against Arebati in Sheol Gaol. In this fight the R number was 900-1500 and network latency was as normal in any normal zone.

It feels as if the networking fixes Square Enix did in Sheol Gaol may be needed in other zones as well.