/gamerule doesn't work at all

The bug

It appears the /gamerule command is not modifying the gamerule values anymore, or rather the modified values don't take effect.

How to reproduce

1. Give yourself some items

   /give @s stone
   

2. Change the gamerule keepInventory

   /gamerule keepInventory true
   

3. Verify the value was changed

   /gamerule keepInventory
   

4. Use /kill

   /kill @s
   

   → The items were dropped