What defines private sites, I wonder – beyond "such as local IP addresses like 192.168.0.1, single-label hostnames, and shortlinks like intranet/"?
How to fix this?
Alternatively, .local domains will work for mDNS-capable devices (and non-mDNS-capable devices if you like to risk things breaking randomly), and the .internal TLD has been reserved so .internal domains should also work for local addresses.