Getting trophies in creative multiplayer

I was playing online with a friend on their world. (Not on realms) and started off in Creative mode. I later hit a command block that switched me into survival. I later hit a diffrent one and go back into creative mode.

 

I first respawnd the dragon with end crystals and got the 'The end again' Trophy.

Normally trophies are locked on a creative world.

Then I tried to spawn a Wither and got 'The beginning' trophy.

 

I suspect It's because of it being multiplayer, the game didn't reconize that it was aworld with cheats.