I'm observing Ma Hatma only reduces damage and has fear immunity while her snowball is flowing. Can anyone else confirm the same observation? I.e. if she is walking or not proccing then all her abilities count for nothing.

I thought it seemed that she dies a lot easier when she isn't actively fighting, but I figured maybe I was just imagining it, since I hadn't seen anyone else say anything similar.

I'm still not sure if it's just "Should Be OP Hero" bias or she actually is dying easier when she isn't actively fighting. I just don't know.

I don't know of a good way to efficiently test the fear immunity, so I skipped that for now. I did, however, go ahead and test the stun immunity just to narrow down when it is probably supposed to be active, if it is actually an issue.

Short Version:
After tossing her into five runs of a dungeon with some maxed out stun towers, I saw absolutely no instances of her being stunned, ever.

So I would guess that the energy reduction and fear immunity are also supposed to be a permanent thing and not fighting/proc related. Whether they are working that way or not, I can't actually say.

Detailed Version:
This was tested out five separate times on Insane Dungeon 3-7 against the six maxed stun towers in a row at the top of the base.

I tossed her out toward the center of the line of towers, with room to travel to them, to allow for maximum chance to stun her before she obliterated them. She was never stunned a single time, despite being "shocked" by the towers repeatedly.

Not sure how much that information helps in narrowing things down, but... I had the time, so I figured why not. It might help.

Or maybe I just wasted a few dungeon runs.

Just did some testing vs Gunslinger in expedition. Dropped Ma Hatma in an open area, waited for GS to proc, then let GS proc 1 or 2 more times after Ma Hatma had started attacking buildings.

Every hit from GS proc was in the same range, it didn't drop once Ma Hatma began attacking. 75% damage reduction is always in effect.

I've noticed PK really beats her down.  I think the scatter from PK's proc is often stopping her from proccing.  She seems to take a lot of damage also.  Will keep a closer eye.

Here's what I noticed. Her stun immunity is permanent while the 75% DMG reduction is only when she procs. When she's walking the DMG reduction doesn't come into effect.