I've heard several people who were there at the time mention it, so yes, "seriously". Apparently they caught the shinki responsible recently, but there's nothing saying something similar couldn't happen again.

[Not to mention how suspicious Yuri had been when he'd been messaging her about the flowers as well that the old gods might've set someone up to take the fall. Shun might get on better with Suijin than most of the old guard, but he's still not fully ready to trust her.]