I also have Magura MT-4 on my Haibike and they are not good. The front has a 200mm rotor and it chatters when hot. I cleaned the rotor with alcohol with no improvement.
I found that Jenson USA has genuine Magura MT 7.4 "Performance" pads for $6 a pair. Dirt cheap. I ordered some and when they arrive, I'll see if they fix the issue. Magura has three levels of pads and I do not know what came stock on my bike, but if new pads don't fix the heat chatter, the brakes are going in the trash in favor of some Shimanos.
https://www.jensonusa.com/Magura-MT-...rmance-Type-74
From the Magura website:
MAGURA DISC BRAKE PADS:
To be prepared for all riding conditions, you can choose between three different brake pads: "Performance", "Comfort" and "Race". Available for all MT brake models, these pads come with single linings or double linings for 4-piston callipers.
Comfort Pad:
"Comfort" brake pads are very interesting for riders who value the best possible modulation. Beginners especially will appreciate the good-natured braking behaviour and the long service life of these brake pads.
Performance Pad:
These pads are suitable for all riders who are looking for excellent performance and a high level of durability. Whether on extended tours or on long bike park days, the "Performance" brake pads will always stop you safely.
Race Pad:
These brake pads really bite! They're designed to deliver the best possible braking power – in all conditions – and are recommended for racing aficionados and performance-oriented riders who need short deceleration times at high speeds."