Area mod - "Monsters Penetrate 25% of Elemental Resistances"

Unless something has changed about the way penetration fundamentally works in PoE2 (beyond the "can't go below 0" thing), that area mod is, effectively, double damage from elemental hits for a character that's normally at 75% ele res. Am I wrong about the math here? Did something change relative to PoE 1? To put this in perspective, the tier 17 mod in PoE 1 is 15% resistance penetration.

The way I see it, say you're at 75% max res (overcapping does nothing here). 25% of that is ignored, so you're effectively at 50% ele res in areas with this mod. You're now taking 50% of the elemental hit relative to the 25% that you were taking at your usual 75% res. That's double elemental damage from hits.

The only thing that's worse about the minus max res modifier is that it also affects DoTs, but the magnitude of the minus max res modifier is more reasonable (-10-15%, I think?). These can also roll on the same map, but running that is up to you.

I feel like it's already a little rude as a map mod (relative to others that grant similar bonuses to waystone find), but I got that modifier on Simulacrum. You can at least not run maps with this roll, but getting it on Wave 11 of Simulacrum is not something I can really walk away from or do anything about. (...which leads into another question of what kind of builds should be able to clear +0 Simulacrum; is this going to like PoE 1 where only a small subset of builds can consistently clear it despite clearing all other pinnacle content?).

Yeah penetration in PoE1 and PoE2 function differently. In PoE2 it just subtracts -25 from your resistance. I'm not sure if over-capping resistances counters penetration or not in PoE2. I heard over-capping does counter penetration, but that was from an unconfirmed source.

Resistances in general has dumb and archaic scaling that feels really awkward. I have a hole post about it if you're interested:
https://www.pathofexile.com/forum/view-thread/3629096

+1 to Simulacrum issue
Can clear max tier breach (actually doing boss mechanics not one shotting), died on tier 0 simulacrum to rng mods (wave 11)

Seriously i got 90 max Res 4k life etc.. and still get one shotted sometimes by bosses when i got this mod

Yeah, I had this one yesterday on a waystone. I play a Smith with 90% elemental res and 3k life. Went into the map, leap slammed towards a group of fire porcupine mobs and was one-shot in the air lol. Map was damn near unplayable.