Still unexplained behavior for heat scale

Stealth prophet?

I have found as well as pocus that at times for no reason at all; my scales will change without any accompanying message, deep in my own territory and domain in full effect (8 or 9)(including my capital) for no good reason other than what I assume is a stealth unit. Though most of these provinces have 20+ defenses (to deal with Call of the Wind) and I assume they are doing their job patrolling.