Graves ult ghouls became stuck when tombstone placed near Sapphire t1 camp

[tuninator]

Match ID: 70137358

Timestamp: 6:03

I placed Tombstone next to the vent-side stairs for this Sapphire tier 1 camp. The ghouls which spawned from the initial summon, and some (but not all) which spawned afterwards, became stuck on the rock near the tombstone and did not move to attack enemies.