Esta had some time to think about this issue, while they were drifting down the river. Part of his mind had to maintain concentration on Detect Magic, but only a part.
What is it, actually, about Esta, that is shaped like Asmodeus and His concerns?
Whatever it is, it hasn't been getting a huge amount of natural exercise while Esta is on this alien planet far from Cheliax's tyranny and the Church's slaves; in the sole company of an Outer-God-touched woman who seems to wobble, in some alien way, between seeming Lawful Good and Chaotic Good. A woman whom Esta does not presently dare to try to discipline, rebuke, nor dominate by more than the occasional sentence of assertion.
It would be little wonder if Asmodeus was having trouble seeing Esta, in that moment, for more reasons than distance.
Esta has nobody here to tyrannize.
And there hasn't been anyone visible nearby who might scare him or command him, for three days.