MustBeBlockedByAllSourceEffect on Golgari Decoy behaves incorrectly, blocks gameplay

[atomicinf]

The MustBeBlockedByAllSourceEffect on mage.sets.returntoravnica.GolgariDecoy is interacting incorrectly with the 'declare blockers' step, making the game impossible to advance under certain conditions when the game flow should not be blocked.

Example of the problem:

• Put a Golgari Decoy and Adaptive Snapjaw in play on your side, and a Rakdos Cackler, Blistercoil Weird, and Smog Elemental in play on the opponent's side.
• On the opponent's turn, have the opponent attack with the Smog Elemental. It is flying, so neither the Golgari Decoy nor the Adaptive Snapjaw are able to block it.
• Attempt to skip 'Declare Blockers'.
• Be informed that 'some creatures are forced to block certain attackers: Golgari Decoy Adaptive Snapjaw'.

[LevelX2]

I'll check this. Thanks for pointing out.