The specific rule for xONEx is that first flight must be within 1 year of issue date, and last flight within 1 year of the first fllight (or as long as 2 years from issue date); this sometimes confuses some Aagents

While any OW airline can reissue any OW ticket, they are not required to, and can insist that the issuing airline do the reissue. Sometimes it is a lot of work for them to do a reissue, hence the reluctance to do it (the tax recalculation alone is daunting). The poor interfaces between QF and AA systems is probably a contributing factor to QF reluctance to touch AA (along with there often being irregularities in existing AA OWE tickets).