Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.11.3

Error message:
Stream write error

Traza de la pila:
(0036712F)
(003670B3)
(003620FC)
(006D4970)
(0068E089)
(00807187)
(0037AFC7)
(0037BCBC)
(0001B4B4) USER32.dll
(0001B5B2) USER32.dll
(0001BBE4) USER32.dll
(0001BC3B) USER32.dll.DispatchMessageW

Status: unknown_rel_addr

I know how to reproduce the problem or the problem happens frequently enough. I wish to be contacted by the WinSCP team to help resolving the problem.