If the gamerule doMobLoot is set to false, a baby panda sneezing never causes a slimeball to drop. Given that MC-61006 is intentional, I would expect this gamerule to not affect baby panda sneezing.

How to reproduce

1. Place the attached datapack in your world's datapacks folder and ensure it is enabled. This datapack makes baby panda sneezing always drop a snowball, rather than having a 1/700 chance.
2. Use the following command to spawn some baby pandas:

   /summon panda ~ ~ ~ {Age:-99999,MainGene:"weak",HiddenGene:"weak"}

3. /gamerule doMobLoot false

Expected result

Sneezing baby pandas could still provide a slimeball even if doMobLoot is set to false.

Observed result

Sneezing baby pandas cannot provide a snowball when doMobLoot is set to false.