DMVPN + Multicast Question about "ip pim nbma-mode"

So from my testing with CSRv's I see that these behaviors apply:

spoke to spoke multicast over dmvpn requires hub use "ip pim nbma-mode" (assume all PIM SM config is okay)

hub to spoke or spoke to hub multicast over dmvpn does NOT require the command (assume all PIM SM config is okay)

Does that sound correct?

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Here's something really strange I noticed with IOU + IOSvL3, so I switched to CSRv.

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Hub to spoke traffic seems to go to ALL spokes no matter what (even with nbma command)

spoke to spoke traffic seems to go to all spokes no matter what

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Here's the hub:

interface Tunnel1

ip address 10.0.0.1 255.255.255.0

no ip redirects

no ip split-horizon eigrp 1

ip pim nbma-mode

ip pim sparse-mode

ip nhrp network-id 1

ip nhrp registration timeout 60

ip nhrp redirect

ip summary-address eigrp 1 192.168.0.0 255.255.0.0

tunnel source GigabitEthernet1

tunnel mode gre multipoint

tunnel key 1

tunnel vrf WAN

end

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Here's a spoke tunnel:

interface Tunnel1

ip address 10.0.0.4 255.255.255.0

no ip redirects

ip pim sparse-mode

ip nhrp map multicast 1.0.0.2

ip nhrp map 10.0.0.1 1.0.0.2

ip nhrp network-id 1

ip nhrp nhs 10.0.0.1

ip nhrp registration timeout 60

tunnel source GigabitEthernet1

tunnel mode gre multipoint

tunnel key 1

tunnel vrf WAN

end

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