Units that the AI faction got from a settlement that rebelled to it, perhaps? Such units often have messed up stats.
Indeed, if it has anything more than bronze upgrades on weaponry/armour, it's a rebelled unit (subject to vanilla RTW mechanics).
It began on seven hills - an EB 1.1 Romani AAR with historical house-rules (now ceased) Heirs to Lysimachos - an EB 1.1 Epeiros-as-Pergamon AAR with semi-historical houserules (now ceased) Philetairos' Gift - a second EB 1.1 Epeiros-as-Pergamon AAR
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