If scanned asset type information is not correct, you can always manually override the asset type by following the instructions in
this knowledge base article.
We use an extensive procedure to try and determine a device's asset type, but this procedure is not foolproof. SSH scanning specifically is actually only supported for *nix based systems like Linux, Unix and Mac, so it wouldn't surprise me that a device scanned with SSH (and no other protocol) would be detected as Linux. Network devices like access points, printers and switches are ideally scanned through SNMP.