Yes. In my experience, it usually comes down to "Our Windows admins don't know Linux, so it'll be easier for them to manage a server if it's running Windows!"
Except they never do, because they don't know PHP on Windows either and are afraid of breaking things, and the customer ends up with a PHP/Wordpress installation that is 4 years out of date.
Luckily, most of those are internal-only apps, but it still sucks.
Where I used to work, we developed and supported a SaaS app based on PHP with PostgreSQL and Apache. We had two self-hosting customers who ran on Windows Server with SQL Server for the exact reasons mentioned, and they were our most troublesome customers. Performance tuning (and hence regular complaints that 'our' app was horribly slow) was a particular issue - mostly due to their admins' lack of relevant experience on both the stack...and Windows Server(!). The whole setup was a pain because we got so much flak, despite the premise of 'self-hosting' being that the customer had sufficient smarts to support the infrastructure and stack and we'd just support the functional and development aspects of the app.
One customer also had the system so locked down that for remote admin we had to connect to a jump box via VPN + RDP and then jump from that to the server with another RDP connection. Fetching large log files through that setup was a challenge.
Partly for our sanity, we persuaded one customer to let us migrate them to a Linux server; that went very well and really cut down on angst all round even though we then took responsibility for platform support.
I don't blame the customer in these cases. The product shouldn't have been sold, or at least not sold with support, if the consumer was going deviate from build specs.
In my limited experience, this is the sales team saying 'anything' to get the sale.
Same here. I have been using PHP since it was publicly available after having used Perl for years (and even having written my own 'php' in perl before php; I did not know at the time that php was basically the same thing; a bunch of $source ~= s/(.)<\?(.)\?>(.*)/print $1;eval($2);print $1/isgm; kind of expressions) cgi-bin and even in heavy Windows shops end of the 90s, I have never seen it hosted on Windows.
Except they never do, because they don't know PHP on Windows either and are afraid of breaking things, and the customer ends up with a PHP/Wordpress installation that is 4 years out of date. Luckily, most of those are internal-only apps, but it still sucks.