UserAgent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36

Steps to reproduce the problem:
when offer proto values:'UDP/DTLS/SCTP' which is correct format according to https://tools.ietf.org/html/draft-ietf-mmusic-sctp-sdp-21 .
Offer:
v=0
o=- 8669542549863514933 2 IN IP4 127.0.0.1
s=-
t=0 0
a=group:BUNDLE data
a=msid-semantic: WMS
m=application 9 UDP/DTLS/SCTP webrtc-datachannel
c=IN IP4 0.0.0.0
a=ice-ufrag:mhgJ
a=ice-pwd:Ae2CIifBoXLITxOcicRiPZgx
a=fingerprint:sha-256 24:EA:41:80:92:F3:9A:06:F8:FC:E6:FE:63:37:6B:99:9F:BC:5D:AF:19:C0:D9:22:44:C2:36:25:ED:83:A5:59
a=setup:actpass
a=mid:data
a=sctp-port:5000
localPeerConnection ICE candidate: 
candidate:2999745851 1 udp 2122260223 192.168.56.1 59558 typ host generation 0 ufrag mhgJ network-id 2
localPeerConnection ICE candidate: 
candidate:3494966876 1 udp 2122194687 10.10.192.131 59559 typ host generation 0 ufrag mhgJ network-id 1
localPeerConnection ICE candidate: 
candidate:4233069003 1 tcp 1518280447 192.168.56.1 9 typ host tcptype active generation 0 ufrag mhgJ network-id 2
localPeerConnection ICE candidate: 
candidate:2664630956 1 tcp 1518214911 10.10.192.131 9 typ host tcptype active generation 0 ufrag mhgJ network-id 1
-----------------------------------
In answer we receive answer:
v=0
o=- 76647901151048540 2 IN IP4 127.0.0.1
s=-
t=0 0
a=msid-semantic: WMS
m=application 0 UDP/DTLS/SCTP webrtc-datachannel
c=IN IP4 0.0.0.0
a=mid:data
a=sctp-port:5000

Media port value is 0 suggesting a mute and thereby no candidate is generated which is wrong since UDP/DTLS/SCTP is valid proto value according to draft and should generate valid answer SDP with candidate generation

What is the expected behavior?
Data Channel shouldn't be muted and candidate line should have generated at answer side

What went wrong?
candidates were not generated and port value was set to 0

Did this work before? No 

Does this work in other browsers? N/A

Chrome version: 58.0.3029.110  Channel: stable
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: