Other airline fare class on AC codeshare
It is presently very difficult to discover what fareclass on a Star A partner is the AC codeshare displayed.
As AC codeshare flown on other *A airlines accrue status miles differently, it is presently very challenging to know what fareclass SQ, UA et al. the AC codeshare maps out to the other airline.
Solution: Make the AC codeshare transparent at booking eg T+ equals Xfareclass on SQ or S on UA or Z on TG. This would eliminate the unpleasant surprise that an AC codeshare on XYZ star partner earns zero status miles.