{Still continuing current Roma campaign under 1.2.3 + Battle pack...}
Having taken an Illyrian Auxiliary Camp to L3 - I would note that Illyria (famed throughout the majority of the Roman period for their horsemen and horse breeding - let alone the plethora of Equites Illyricani} - cannot recruit any cavalry.
Any chance this anomaly could be addressed? Noting that the mercenary cavalry do still remain present.