This article describes whether MC-LAG is supported with P-VLAN.

Is it possible to configure MCLAG with private VLANs?

MC-LAG with PVLAN (Private VLAN) is not supported on Juniper switches.

Below is the list of features that are not supported on PVLANs on Junos OS switches with support for the ELS configuration style:

• Egress VLAN firewall filters
• Ethernet ring protection (ERP)
• Flexible VLAN tagging
• global-mac-statistics
• Multichassis link aggregation groups (MC-LAGs)
• Port mirroring
• Q-in-Q tunneling
• VLAN Spanning Tree Protocol (VSTP)
• Voice over IP (VoIP)

Refer to the link below for more information:

https://www.juniper.net/documentation/us/en/software/junos/multicast-l2/topics/topic-map/private-vlans.html#id-limitations-of-private-vlans