Region flag to freeze fire completely

WORLDGUARD-3734 - Reported by narwhal

I am attempting to make a permanent fire for a fireplace. The region it is in has the fire-spread flag denied. However, the world has fire spread intentionally enabled both in WorldGuard's config.yml and with the Minecraft game rule, which is probably part of the issue. I remember probably a year or two ago (before /gamerule existed) I could deny fire spread for a WG region, light wood on fire, and it would stay lit. Now if I do this, it goes out after a minute or two. Could a flag be added to "freeze" fire completely for a region, or is there a way to do this that I'm missing?