I seems that you have posted log file for a working session only.
You possibly use the same log path for all your sessions. The logs overwrite. You have to use a unique (e.g. timestamped) name for every session.

Hello
Thank you for the response.
As advised, I herewith attached debug log information. Please note, if I specify the session debug log file explicitly, I am running into another file locking issue as it is running on a multithreading environment. The platform I am using here is .NET Core 3.1 services deployed on Windows 19 server. I am able to get the log by creating a separate debug log file for each host to avoid the thread locks on the file while writing on to the file. This is another issue in the multithreading environment. The bug I reported earlier in the subject line was deployed without specifying any session debug log file or regular session log file. As I said it was working fine and downloading files from at least 10 different hosts at least 5 to 6 times then the error pops up. This has been scheduled thru the hangfire component and the job triggers the program to download files for every one hour. Anyhow i am attaching the debug log here. Thanks in advance. Your help is appreciated.

Please enable debug logging (Session.DebugLogPath) and post logs both from working and failing session.

Hello
I have a windows service developed to download autopilot for every 1 hour. It is developed using .NET Core. Service was deployed in one of the machines, Service runs and downloads files at least 3 or 4 times then it's throwing an exception WinSCP process terminated with exit code 3. as below.

ListOfRemoteDirectories, Error details:WinSCP.SessionLocalException: WinSCP process terminated with exit code 3. There was no output. Response log file C:\Users\filetransfersvc\AppData\Local\Temp\wscp2EA8.009B9DC9.tmp was not created. This could indicate a lack of write permissions to the log folder or problems starting WinSCP itself.
at WinSCP.Session.Open(SessionOptions sessionOptions)
at ECI.EDI.WinSCPExtension.WinscpExtension.ListOfRemoteDirectories(IFtpInfo _ftpInfo) in C:\agent\_work\81\s\ECI.EDI.WinEcpExtension\WinscpExtension.cs:line 400.

If I restart the service then it works for three four run again and getting a same exception. Your help on this will be greatly appreciated.