The spirit bloom does have an effect of the Templar chest. It's not every time, but last week I was helping a team of randoms get through the raid and one disregarded my advice to not pick up the spirit bloom chest and as soon as he did the Templar chest despawned. Like I said, it doesn't happen every time but I'm absolutely 100% positive that it does have some kind of effect. Maybe if you get the spirit bloom chest it despawns a different chest each time? I'm not sure but I know there's a chance of despawning the Templar chest if you pick it up so I just skip it every time because I like ascendant materials more than spirit bloom. My guess is it is just a chest put there by bungie to tempt us.