These sometimes split into 3 but it can be between 1 and 3. The guys that spawn at death have a lot less HP, still con dark blue to me at 71 so I'm not sure what level they are.
If you can stand away as it dies the little ones will not agro.
When these mobs are killed they split into 3 separate mobs. While these mobs are LB to a lvl 80 they do not hit often or hard. The Split Mobs have relatively few hit points.