@spintike: Thanks for sharing your findings! Though I'm not sure what "theory" do you refer to.
Before posting, please read how to report bug or request support effectively.
Bug reports without an attached log file are usually useless.
. 2023-03-20 15:12:33.854 Initialised AES-256 SDCTR (AES-NI accelerated) [aes256-ctr] outbound encryption
. 2023-03-20 15:12:33.854 Initialised HMAC-SHA-256 outbound MAC algorithm
. 2023-03-20 15:12:33.854 Initialised AES-256 SDCTR (AES-NI accelerated) [aes256-ctr] inbound encryption
. 2023-03-20 15:12:33.854 Initialised HMAC-SHA-256 inbound MAC algorithm
. 2023-03-20 15:12:33.869 Remote side sent SSH2_MSG_EXT_INFO after USERAUTH_SUCCESS
. 2023-03-20 15:12:33.869 Attempt to close connection due to fatal exception:
* 2023-03-20 15:12:33.869 Remote side sent SSH2_MSG_EXT_INFO after USERAUTH_SUCCESS
UsePrivilegeSeparationis set to
yeson the server.
1) successful transfer using a newest version of WinSCP that still works (5.21?)
2) failed transfer after upgrade to 5.21.1
3) failed transfer after downgrade to the same old version
I reimaged one of my devices for testing purposes and had no issues. Installing an older version of WinSCP caused no issues as well. When I updated to the latest version, the issue returned and I could no longer copy for extended periods of time through WinSCP.