Async replica automatic failover

Dears,
I would like to know or if anyone has faced this before.

In what situation does automatic failover happen to a Async replica?
As, Async replica only supports manual failover, does this setting get bypassed and triggers a automatic failover due to some condition.

No, it does not support auto-failover. Async failover could cause loss of data, and Microsoft's HA features do not support any automatic failover scenarios where that could occur.