I've realized an annoying bug; If a Grim Bahir or Skycatcher kills its target, it does no splash damage to nearby enemies.
Is this documented?
e.g. : Image, note that the living ice barrier should have 150 HP remaining as Skycatcher has siege.
It appears that these units synchronously do damage and then splash while Wyrm or Lost Dragon simultaneously apply damage and splash. Quite an important bug! (edited)