Eject Pack:
-Triggers on self-inflicted stat drops (pretty obviously the intent of the item, but just making sure)
-Triggers even if your stats are decreased but stay in the positive stat levels
-Triggers from Stockpile release
-Triggers from allies lowering your stats
-Only one switch per move still applies, though the specific Eject Pack+Weak Armor with U-turn situation outlined only causes the U-turn to go off, not Eject Pack. Parting Shot also denies Eject Pack. I'm not overly sure how this hierarchy worked last gen, but if I'm understanding correctly this means it's at the bottom of it, provided the rest are still ranked the same way.
-Triggers on self-inflicted stat drops (pretty obviously the intent of the item, but just making sure)
-Triggers even if your stats are decreased but stay in the positive stat levels
-Triggers from Stockpile release
-Triggers from allies lowering your stats
-Only one switch per move still applies, though the specific Eject Pack+Weak Armor with U-turn situation outlined only causes the U-turn to go off, not Eject Pack. Parting Shot also denies Eject Pack. I'm not overly sure how this hierarchy worked last gen, but if I'm understanding correctly this means it's at the bottom of it, provided the rest are still ranked the same way.