@crunchy,

I looked through our docs and could not find anything in relation to the SG105, the only similar case is for an older SG105E and was only for a specific hardware version. As far as I know, these switches should have no issue connecting in setups like this, as all it does is forward the connections to the router. If you are able to, you may try configuring the network to not use the intermediate SG105, as this sounds as though its adding additional hops, requiring the intermediate switch to handle essentially 9 Ports of Traffic