I'm not that used to bridge-domains on MX, but I think you are missing adding the interface to the bridge-domain on both MX's:
set bridge-domains vlan-1151 interface ae1.0
set bridge-domains vlan-1151 domain-type bridge
I'm not that used to bridge-domains on MX, but I think you are missing adding the interface to the bridge-domain on both MX's:
set bridge-domains vlan-1151 interface ae1.0
set bridge-domains vlan-1151 domain-type bridge