Date & Time: 8/31/2019
Frequency: Always
World name: Mateus
Character name: Mne Jing
Retainer name: N/A
NPC name: Eshana provided quest
Monster name: Funnel Antlion
Class/Level: MCH 75
Party or solo: Either
In-game time: Irrelevant
Area and coordinates: The Fringes - x15 y22 (or thereabouts)
Housing: N/A

The Ananta beast tribe quest "Funnel and Games" cannot be completed when over level ~71. As these quests are still a decent and quick source of EXP, they're still worth doing when leveling past 70.

I accepted the quest as a 75 MCH, and ran to the area where the Antlions are supposed to spawn. They did not spawn as expected. I changed jobs to 70 RDM, and they did not spawn, which was expected as I did not accept the quest as RDM.

I abandoned the quest, and accepted it again as 75 MCH, to confirm the result. As expected, the antlions did not spawn.

I abandoned a second time, and this time accepted as 70 RDM, went to the appropriate location, and the Funnel Antlions appeared as expected.

Clearly the mobs are unable to aggro higher level players, which is an issue as that is the programed behavior of Antlion-type mobs. I can't exactly confirm what the maximum level to complete the quest is, but that'd be trivial to sort out on SEs end should this be accepted.

Connection/PC specs are irrelevant.