We use the TP-Link SG1024DE in our networks and have identified a bug in the newer versions of the switch. When a IGMPv2 membership query is sent over the switch, if a IGMPv2 membership report is then sent over the same ethernet port, the switch will send this membership report to all other ports which results in the other devices not replying to the initial IGMPv2 membership query.

To give an example, let's say I have router one connected to switch one, and switch one connected to switch two. For the point of this example, let's say switch 1 is an unmanaged switch and switch 2 is the TP-link switch. Then we have computer 1 connected to switch 1 and computer 2 connected to switch.

Router 1 sends a membership query which hits switch 1. Switch 1 forwards it to all ports (switch 2 and computer 1). Computer 1 then replies which is sent down all ports (router 1 and switch 2) because it's an unmanaged switch.

Switch 2 receives the membership query and forwards it on to all ports (computer 2).

The expected behavior from this point is switch 2 then gets the membership report, it adds this to the IGMP snooping table and does not forward it. This is exactly what our other TP-Link SG1024DE v4.2 running 1.0.0 Build 20220825 Rel.69073 does.

However, what happens with our V7 0.0 Build 20230616 Rel.34205 is different. Switch 2 gets the membership query and sends it to all ports which is expected. But it then gets the membership report and also sends this to all ports. This then results in Computer 2 getting the membership report which in turn causes it to not send its report back resulting in computer 2 being left out of the multicast group as the TP-Link never got the IGMPv2 membership request.

It should be noted my example is only an example, that is not exactly how our network is configured but regardless a IGMPv2 switch is not meant to forward membership requests on from the same port that the membership query came on.