Multiple sftp-server.exe running and locking files

"OpenSSH for Windows" version
7.7.2.2

Server OperatingSystem
Windows Server 2019 Standard

Client OperatingSystem
Windows 10
What is failing
When a connection drops during file transfer sftp-server.exe stays alive and locks the file.
Expected output
Can remove or open files after failed transfer.
Actual output
Can not remove or open files and I have multiple sftp-server.exe running (over 10x). Can only remove or open the files if I kill all sftp-server.exe, which can lead to more corrupted files.

I have only one SFTP user connecting to our server.
The config is:

SyslogFacility LOCAL0
LogLevel INFO
AuthorizedKeysFile	.ssh/authorized_keys

Subsystem  sftp   internal-sftp -d "D:\ftp\" -l INFO -f LOCAL0
PermitTunnel no
AllowAgentForwarding no
AllowTcpForwarding no
X11Forwarding no
AllowGroups mydomain\sftpuser

Match User mydomain\myuser
	#PasswordAuthentication no
	ForceCommand internal-sftp 
	ChrootDirectory D:\ftp\myuser
	
Match Group administrators
       AuthorizedKeysFile __PROGRAMDATA__/ssh/administrators_authorized_keys

UPDATE:

I updated OpenSSH to 8.1.0.0 a few months ago. It was working fine but it is locking the files again.

Start by reproducing a dropped file transfer on Windows Server 2019 with the reported internal-sftp configuration, then inspect the surviving sftp-server.exe processes and file locks. Done means a failed transfer no longer leaves the file locked or requires killing all sftp-server.exe processes; the issue names no source file or test to begin from.