FYI for everyone: Lansweeper pulls the manufacturer of Windows computers from the win32_computersystem WMI (Windows Management Instrumentation) class on the computer itself.
I can't confirm this as we haven't received a win32_computersystem output of a problem computer from one of the users in this forum topic, but I assume the information is stored incorrectly in WMI itself. This is not something we can resolve. You can manually override scanned manufacturers though, e.g. by hitting the Edit Asset button on individual asset pages or clicking the Assets link at the top of the web console and using one of the mass editing options on the left.