Total Commander

Two things:
Yes, It was about the android version, at least in the beginning.

Second of all, I solved it:
The Problem with OpenSSH on Windows is the default shell.
You can change the OpenSSH default Shell from propably cmd to Powershell for example via the PowershellCommand:
"New-ItemProperty -Path "HKLM:\SOFTWARE\OpenSSH" -Name DefaultShell -Value "C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" -PropertyType String -Force"
It just creates a regedit entry.
Alternatively you can try Cygwin and use that as shell, it beeing a Linux Port will propably improve compatibility even more, should you actually wish to ssh into your Windows Machine.
However, Powershell already does the trick for what I demand.
I can now swap files at 250 MBit's via SCP rather than 30 via SFTP (250MBits is the max for my one antenna 5GHZ Phone, so the sky is unlimited).

Hi, I just stumbled upon this thread after experiencing the same problem + solution.
I'm just here to emphasize I encountered this problem when connecting to my Synology's sftp service - so quite a common solution => many people might encounter it too. Maybe a better notice in the app would be great, just to say for instance "try to disable SCP if xfer error" or "disable SCP if Synology NAS"
I suppose Syno doesn't support scp.
No pb for a regular ssh/sftp/scp server.

Beside this, I'm a loooooong TCMD user - I paid it I think in the beginning of the century o_O (my licence's postal address is so old, I see it each time I start TCMD ) and I can't use anything else on a windows computer. Today I removed all android FTP/SFTP other clients I tried. They're never good, stuffed with ads, not working correctly and so on. I just realized a bit late Android/TCMD had a sftp plugin. Hum (am I that stupid, I've been using the sftp plugin on windows for years...). Thx for all these years.