The fact an interceptor may keep on firing at a shot down target is not a bug per se (if this occurs in the last second), but this seems to generate sometimes a side effect (a transient anomalous animation).

What's weird on the screenshot here, is that the UFO seems to have been shot prior to the last beam, or perhaps, prior to the display of the last beam, so that the engine couldn't correctly work. The expected behavior would have been to draw the last beam as if the UFO was still in the air.

Experienced with a twin PBW Saracen against a Fighter.

Perhaps the order of some actions should be reviewed, or some temporizing or test added?

Note that in the precise case, the Saracen was displaying another strange behavior, that is, when arrived at weapon range, it turned 180° and kept on firing while flying ahead of the UFO, in the same (northward) direction, thanks to the omni-directional ufo:ai firing system. The light blue ray is of course the odd PBW beam.