Item drops even with keep inventory on

In my survival realm, I turn on cheat and have keep inventory. And I checked that I always have keep inventory on. So, when I want to go back home, I just kill myself or teleport home.

There are 3 times that item drop on death even with keep inventory.

1. I teleport home but Y coordinate is too low so I suffocate to death.
2. I want to go back home, so I teleport myself up to Y 300 to fall to death.
3. I just /kill @s to go back home

Right after I died I query gamerule and found that keep inventory is still on.

Since the pale garden update, all of these make my item drop just once for some reason. I still can't find way to reproduce these. (when I try to die the same way but it just does not happen again)