Many IPTV providers do not support PIM (at least to their customers). Their edge devices simply snoop/forward the IGMPv2 messages out their WAN interface, regardless of IP or RP configuration.
By adding an option to IGMP-Proxy to force a specific version (likely just version 2 for almost every provider). In fact, I’d even be willing to write a patch to make this happen! On my own dime! (Oh, except I can’t patch anything because it’s closed source.)
Here’s the part where I grovel… pleeeaaassseeee 