[Bug 1.1][Cannot Target Unit that Retreats off Tactical Map with Ranged/Spells/Abilities]

This has a few similarities to the bug I posted in this thread, where a unit on a broken tile cannot be targeted by ranged or magical attacks but can be by melee attacks.  Yours looks much stranger, though.

All I can say is that is the T_Barren_Desert_02 tactical map. Who knows how the little spider thing moved up on that perch.

I just saw an AI unit apparently move off the tactical map, like in the OP, but on a different map.  I'm not going to be able to test whether it can be targeted by ranged units, though, since I'm playing as Yithril which has no ranged units.  See here at the bottom:

Still can't see how they did that (seems to be a deeper code problem), but that map is

T_Grassland_Fertile_04

I thought maybe since it was a boundary of 1 deep of blocked tiles was the problem, but this has a full set of blocked tiles. It seems that the AI is utilizing a pathing that is not available and it's bypassing the map information.

What I do notice in common is that each of these units are ranged units and on each of these maps the location of the backup is 2 away from a start location. I wonder if the AI always allowed to move from its start position and a check for the block tiles are not being initiated (works off the assumption that the ranged unit can always move back once). All speculation unless Frogboy tells why this is happening or lets me look at the deeper code.

I don't recall ever seeing this problem before 1.1.