Logfilepath throws errors

[benohara]

In data/common.yaml active_directory::dns_server::logfilepath is set to '%systemroot%/system32/DNS/Dns.log'

When puppet runs, the dns server logs an error that it cant write to c:\windows%systemroot%\system32\DNS\Dns.log (with the literal %systemroot% in the error.

It doesnt appear to change the setting in the dnsserver itself, thats stays set to '%systemroot%/system32/DNS/Dns.log'

If I change active_directory::dns_server::logfilepath to "$facts['system32']/DNS/Dns.log" then puppet applies without the error, the setting in dnsserver is updated to c:\windows\system32\dns\dns.log

Not sure why or what is causing the error.