Mtr ignores --interface and --address

Hello,

I want to diagnose some packetloss on one of my wan links. I have 3 uplinks and use mwan3 to manage them.

Ping -I ethX dst

does work and uses the interface i do specify.

mtr -I ethX dst

does not work and it uses instead the default route.

Is there any other config parameter for mtr needed that I miss?