If you kill a unit with the sword Pyre Brand, an inferno appears in it's tile. However, if you kill a second unit in the same tile, the visual of the inferno disappears. The damaging effect still remains, though. I'm not sure, if this also happens with the Soulburning spell or just with the ability of Pyre Brand, as the AI wasn't cooperating during my test battles.

Another visual bug is, that enemies simply disappear, if they are killed by the fire damage from Pyre Brands Soulburning ability.