igmp-proxy for IPTV

RouterOS General
1

I setup igmp-proxy on my hEX PoE for IPTV and I get stream on my tuner.
However, it looks like traffic is passing on all ports on the hEX and not just the port to the tuner. How can I limit this?
This is what I got:

/routing igmp-proxy interface add comment="" disabled=no interface=ether1 threshold=1 upstream=yes
/routing igmp-proxy interface add comment="" disabled=no interface=bridge threshold=1

ether1 is my WAN port and ether2-5 is LAN on the bridge.
My STB is connected to a unmanaged switch on ether3.

2

This link might help ?

https://community.bt.com/t5/YouView-Boxes/Extra-IPTV-channels-working-on-Mikrotik-750G-router-a-short/td-p/1137730

3

Thanks for the link, nikc.
I followed a short howto that looks a lot like this one to get where I am.
What is different from my setup is that the input UDP firewall rule is not needed and does not look to make a difference? I only need the igmp input rule and the UDP follow rule.
Also regarding the igmp-proxy settings, the guides says to set the downstream interface to the one where the stb/tuner is connected. Mine only works if I chose the bridge for downstream. Why is that?