Photos app URI scheme broken?

Is the https://learn.microsoft.com/en-us/windows/apps/develop/launch/launch-default-app#photos-app-uri-scheme broken since Microsoft Photos App version 2025-11010-9001-0?

For example when you try to start this:

ms-photos:viewer?fileName=c:\users\userName\Pictures\my%20image.jpg

Filenames in this scheme should be URL encoded, right? Or at least accept URL encoded filenames. 

Information about URI schemes can be found https://learn.microsoft.com/en-us/windows/uwp/app-resources/uri-schemes, which refers to https://www.ietf.org/rfc/rfc3986.txt for the syntax.  The complete URI syntax is collected in Appendix A, which defines the query part as:

   query         = *( pchar / "/" / "?" )

And  pchar as:

   pchar         = unreserved / pct-encoded / sub-delims / ":" / "@"

And pct-encoded as:

   pct-encoded   = "%" HEXDIG HEXDIG

So the encoding "%20" should be accepted, should it not? But it seems this is no longer the case.

See also https://www.ghisler.ch/board/viewtopic.php?p=468413#p468413.