There was an issue in a previous build whereby the scanning server wasn't filled in for non-Windows assets that had only been scanned by LsAgent. This was fixed in the initial 7.1 release. Below I've pasted the relevant changelog entry, a link to Lansweeper update instructions and a link to our changelog. I recommend updating both Lansweeper and your LsAgent installations. I've included the download link for LsAgent below as well.
Fixed: LAN-1784 If a Linux or Mac computer is only scanned using LsAgent, its Scan Server value is blank and its Scan Status is set to “scanserver unavailable” in the web console
https://www.lansweeper.com/knowledgebase/updating-your-installation/https://www.lansweeper.com/changelog/https://www.lansweeper.com/download/lsagent/Keep in mind that this issue was cosmetic in a lot of cases. The main purpose of the scanning server value is to have scans initiated with the Rescan buttons directed to the correct scanning server. Hitting Rescan triggers an agentless scan and is not going to work anyway for assets that cannot be scanned agentlessly. Your assets might be scannable without an agent at some point though, if you set up a VPN.