The zombies at the Blighted Outpost on Lesser Aradoth were renamed in a recent update and also had their level raised. I recall from playing previously they were in the 5-10 range. Their HP still reflects that as they have only about 150-180hp despite being level 16-18ish. Note that the cleric zombies seem fine HP wise, it's only the fighter types. This is the outpost at 20308,23227.
It seems as though their level/names were updated, but hp was not.