Unable to use scp with -oUserKnownHostsFile that has spaces

[cbookg]

"OpenSSH for Windows" version
v7.6.1.0p1-Beta

Server OperatingSystem
Linux - Ubuntu

Client OperatingSystem
Windows 10 Enterprise

What is failing
When launching ssh and scp from another process, I'm passing in arguments to specify a known hosts file and key. Note I'm not launching these as a shell process.
For ssh,
Command = C:\PathToSSH\ssh.exe
Args = [
-FNUL -ic:\space test\ssh\id_rsa,
-oStrictHostKeyChecking=yes,
-oUserKnownHostsFile="c:\space test\ssh\known_hosts",
myuser@myserver
]

For scp,
Command = C:\PathToSSH\scp.exe
Args = [
-FNUL -ic:\space test\ssh\id_rsa,
-oStrictHostKeyChecking=yes,
-oUserKnownHostsFile="c:\space test\ssh\known_hosts",
sourcefile myuser@myserver:/targetlocation/
]

Expected output
Both commands succeed.

Actual output
The ssh commmand works as expected.
The scp command fails with this error:
ssh: Could not resolve hostname test/ssh/known_hosts: No such host is known.

Since scp appears to invoke ssh, it appears that it is not properly passing in the path with spaces.

[cbookg]

The "arguments as array" example was for launching from Go.
I've reproduced the problem in C# as well, using triple-quotes to pass the quotes through the process object (since it takes arguments as a single string). This is the equivalent string being passed into C#'s ProcessStartInfo.Arguments:
... -FNUL -oStrictHostKeyChecking=yes -oUserKnownHostsFile="""c:\space test\ssh\known_hosts""" ...

Again, this works for launching ssh, but not scp.

[cbookg]

After looking into this a bit, I believe the spawn_child_internal function needs to escape arguments containing string when it generates the ssh command line.

Currently it builds the command line by taking every arg in the list, adding a space to the command line string and then adding the arg surrounded by quotes. This results in a command like:
... "UserKnownHostsFile="c:/space test/ssh/known_hosts"" ...

The inner quotes likely needs to be replaced with something like " or """

[cbookg]

In my last line the backslash was filtered out of my comment. Should have been (backslash)" or """

[cbookg]

It looks like this may be fixed, but there hasn't been a release since July to pick this up. Is there an ETA for the next release?