Re: pure L2 multicast traffic (no multicast ip traffic) not forwarded

You can disable igmp-snooping on vlan level.

set protocols igmp-snooping vlan <vlan-name> disable..

Follow the kb fyr..

https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/disable-edit-protocols-igmp-snooping-ex-series.html.

If you are having a trunk port, you might see the behaviour of igmp-snoopimg disabled for all the vlan as mentioned in following kb..you may follow the work around if you are facing the same issue..

https://kb.juniper.net/InfoCenter/index?page=content&id=KB23482