Firiona Vie Cliffs
 

Over by where the Drolvarg growlers, snarlers and pirates roam. Also known as the Firiona Vie Cliffs. While fear kiting them near the cliff edge they'll path down the cliff side.

But here is the major issue. When the fear ends and they run back to the player, presuming the player has agro. They don't path back up the cliff side and rather path into the ground. then pop up at the player when they're close enough to engage in melee.

My pet also doesn't path up the cliff side when returning. It also pathes into the ground and then pops up out of the ground when it's close to it's final destination.

Here are some not precise, general locations in which this happens.
These are not the only places this can happen.
-3014, -1833
-2976, -1788
-2857, -2152

I would label this a game breaking issue.
edit: Also once they're in the ocean water, beyond the cliffs. You can't get line of sight on them out of the water or in the water. It's totally broken and extremely frustrating.

Video clips of pathing issue are most helpful with loc references (which you already provided)

I need to revise some of the things I stated in the OP.

There are some area's on the cliff side that the mobs path up correctly, most of the time. It's a long stretch of landmass but it feels like these spots are in the minority.

Line of sight in the ocean, I can usually cast on mobs that are feared into the water. It's when the mob engages my pet in the water after fear breaks/ends, things get, weird.

I want to add, I recall this all becoming a 'thing' when haynar changed the pathing code. I'm sure you'll more well remember when people were complaining about dragons falling through the floor in ToV. It was around then. (aprox oct 2019-dec-2019[1][2][3])

I'll try to get some videos.