Glad they resolved the sticky extraction issue.
Doesn't automatically mean any remaining ejection pattern issues are necessarily gun-induced, though. Or, at least, only gun-related.
Shooter grip/wrist lock and ammo power (over or under-powered) probably ought to be considered, as well.
How experienced are you in shooting diminutive plastic pistols, anyway?
How many total rounds have you fired through the gun? What brand of "hollowpoints? were you using?
If it were me, and the slide could be manually retracted and locked back (EMPTY gun), meaning good slide movement and length of travel, I'd not discount it might take some more range time for the stout little recoil spring assembly to reach a "worn in" state of tension. Might be exacerbated by using ammo which might be at the lower end of the normal power levels, too. No way to know without being there to see the gun and ammo, watch you shoot it, shoot it myself, try different ammo, etc.
I've tried some different Shield pistols from both early and recent production, chambered in 9 & .40, using normal duty ammo (124gr +P and 180gr) ... and watched other guys shooting them, and the guns have all run normally in different hands. Doesn't mean someone might not come along who needs some more familiarization time, like a minor revision of the their shooting grip.
If you return the gun and it doesn't exhibit ejection pattern issues for the guy test-firing the gun, using whatever American-made major maker ammo is currently sitting on their shelves at that time (they vary, I'm told), how do you expect them to "fix it"?
Maybe try some different ammo?
Dunno. Just some thoughts.