It looks like Mythic Raszageth also got some stealth hotfixes with the weekly reset, nerfing various aspects of the Mythic encounter.
There could be more changes to health that we are unable to datamined, but these are what we have found so far.
Edit #1: We’ve heard that the Raszageth adds have received a 50% health nerf in the first intermission.
The Colossal Stormfiend crackles with energy, inflicting 80316424 Nature damage to all players every 2 sec.