SFTP failure: Unexpected timeout

I am having issues with the fetch command. I am trying to upload a export to a remote server over sftp

Command:

/tool fetch upload=yes url="sftp://server/testbackup.rsc" src-path=testbackup.rsc user=admin idle-timeout=600

After a about 4 seconds I get this error.

  status: failed
failure: Unexpected timeout


14:04:18 echo: fetch,info Upload to server FAILED: Unexpected timeout
14:04:18 echo: fetch,debug Upload from testbackup.rsc to sftp://admin@server/testbackup.rsc (1.1.1.1) FAILED: Unexpected timeout

Interestingly, the file successfully uploads to my server

RouterOS Version: 7.18.2

I just ended up catching the error in a script. I would be curious to know if anyone else has this experience when trying to use the fetch command.

# The user needs a private key uploaded to the router for authentication with the sftp server. 
# The key-owner needs to match the user's name.

:local sn [/system routerboard get serial-number]

:local fName     ($sn . ".rsc")
:local fNameV    ($sn . "-verbose.rsc")

:local urlBase sftp://your-sftp-server-here/
:local urlFull ($urlBase . $fName)
:local urlFullV ($urlBase . $fNameV)

/export file=$fName
/export verbose file=$fNameV

:do {/tool fetch upload=yes url=$urlFull src-path=$fName user=aws idle-timeout=60; } on-error={:put "catch err"}
:do {/tool fetch upload=yes url=$urlFullV src-path=$fNameV user=aws idle-timeout=60; } on-error={:put "catch err"}

/file remove $fName
/file remove $fNameV