I noticed an bug last night with Nekros, while on IO, Jupiter on a defense mission, activating Shadows of the Dead caused a Sniper Crewman to appear. Since they spawn Ratels, the Ratels would spawn and be marked as allies but still have no particle effects as the sniper crewmen did. This ended up blocking a round (at round 15 of course) and forced us to quit. This has happened to others too, and should be added as a bug.

See:

https://www.reddit.com/r/Warframe/comments/9lez1x/corpus_ratel_bug/

https://forums.warframe.com/topic/796891-friendly-ratels-bug/