Dell OS 9.11.2.2 won't establish bgp sessions with peers with "bgp-evpn" capable peers

Hi, I am aware of the fact that Dell OS 9.11.2.2 doesn't support MPLS but I have tried peering with a cumulus quagga router that's been set to do IPv4 unicast and BGP EVPN routing.-Yes I have seen a part of document from cumulus networks that says their EVPN is based on MPLS.-

I thought it should peer with each other well although Dell OS 9.11.2.2 would disregard all the EVPN paths. - as the cumulus quagga just peers well with Dell OS 9.11.2.2 advertising its capability of IPv4 multicast which it hasn't been set to do. -

but what actually happened was Dell OS 9.11.2.2 stopping the establishment process sending a notification of "OPEN message error - unknown" after receiving a KEEPALIVE from the cumulus quagga.

Is this an expected behavior or a software fault?

Here is the pcap capture file captured on the cumulus quagga ubuntu host in which you can check the failed peering process from the beginning of OPEN messages : https://drive.google.com/uc?export=download&id=0B1xRHpWM_gd4c2pySVJrR3BSMkE

Best Regards,

Gunwoo Gim