Do you have a multicast stream in which it's stopping before getting to the receivers? Do you have a full (S,G) on some devices, but the further you get from source you only have (*,G)?
Check the TTL that is being sent. Some encoders may not send or may not be configured to send a full TTL. If this is the case, the TTL might be expiring before getting to the receiver.
Either check the configuration on the encoder (Source) or take a inline packet capture to check the TTL being sent.
Best way to check the TTL of packets would be to create a port analyzer that would send the mirrored traffic out a specific interface. Connected to that interface would be a device that can do a full packet capture.