I cannot confirm this behavior. With a router running FRITZ!OS:7.57 configured to use Google's DNS (in the router only) I get the following on Windows 10
Update: the connection does have the DNS suffix, so according to the superuser answer linked in OP (which is the first result when looking up what a DNS suffix is), it should get appended to lookups on windows, but it looks like it isn't in my case.
> ipconfig
[...]
Connection-specific DNS Suffix . : fritz.box
I noticed a lot of comments explaining the same thing, but also some confirming my observations. So far it appears the issue is mostly present if you have configured a separate DNS server in the DHCP settings, e.g. DNS is resolved somewhere outside the Fritz!Box. I will investigate further and update the article.