Hello there!
Unfortunately, this is a known issue in the current Lansweeper version (bug ID: LAN-14022). It seems that the asset radar feature can pick up IPv6 addresses and create new assets based on the IPv6 link-local address only, even if there is already an asset in the system (with the IPv4 address).
As a workaround, since you indicate that you don't use IPv6, you can disable the IPv6 protocol in the network adapter's properties on the Lansweeper Scanning server, as shown in the screenshot below. That should prevent asset radar from picking up IPv6 addresses.
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