Targeted mitigation often does not work

[Jeeqbit]

They stopped following that philosophy at the end of StB the battle log telling you what the boss is doing is the most inaccurate way to determine what is Physical and what is Magical.

It doesn't distinguish on player abilities either, just player GCDs. It doesn't seem like a strict attachment but it would be a start if it was.

Eric's Warden's Wrath looks Magical but it is not, it's a Physical attack and then his Slam Shut which is also a raid wide and it looks slightly the same as Warden's Wrath is a Magical

Shining Cells and Slam Shut are arena transitions. Is there an example of a physical arena transition or can we assume all arena transitions are magic?