The Black Sun Monolith boss, Rahyeh behaves erratically when using Decoy with a Rogue.
During the fight, I used a short-fused Decoy to deal burst damage to Rahyeh, and he was definitely fond of striking it down. When he prepares to trail his DoT void flame line, he can change targeting priority and he swoops towards it instead of the telegraphed route.
One time, I happened to throw a Decoy towards the entrance, just as he was taking flight to prepare this ability, causing him to leave the arena in that direction, and it took him a good 20 seconds to return to the arena, softlocking the fight for that duration. He appeared to leave straight towards the entrance and he returned from there, without clipping through the level. He then continued with the Void Pizza phase and the fight commenced as normal.