Hi Alexander,
Thank you for the information. As you state it might as well be a version incompatibility issue between the devices.
It might also be a configuration change that i don't know about. But i checked the configuration page (https://www.juniper.net/documentation/en_US/junos/topics/topic-map/evpn-irb-solution-configuring.html) and this is pretty much how i configured it except ISIS instead of OSPF and i don't have "set routing-options forwarding-table chained-composite-next-hop ingress evpn" But from what i can find this is just a command for helping the evironment scale, not for any function.
Do you have any idea if there might be any other configuration changes?
But then again.. the first few pings work fine so traffic flows. There is just something somewhere that decides that the forwarding should stop after a few packets.