Creature death triggering twice for Murder Investigation?

stikxs

The AI had Patron of the Valiant in slot 1 (disabled by cast out), and the monitor was #2 and spearmaster #3 I believe. My cat had vigilance and killed the monitor and spearmaster, and neither of them were reinforced, but it looks like it counted the spearmaster twice for triggering murder investigation (there are 3 1/1 soldier tokens out now). Also I think the 2 creatures died, then 2 tokens came in, then the exert gem for the spearmaster went away followed by the 3rd token.