When Rem sleeps a Guardian, troopers will walk right past it

[curtis.b.johnson]

When Rem sleeps the enemy guardian with Naptime in lane and there are no other "awake" enemies around, the trooper wave will walk right past the guardian and continue on to the walker. With a large enough wave and little helpers, they can do significant damage to the enemy walker even a few minutes into the game if the enemy team is ganking, or running boxes, or otherwise not paying attention.

The same bug applies to walkers. If an enemy walker is slept with no other enemies around, the troopers will ignore it and continue on to the enemy base. The same bug also applies to other sleep abilities like Haze's sleep dagger.