Stack trace - try to reconnect on a RPi, that reboot.

(006C8C4D)
(006C3C14)
(00098B63)
(00017482) KERNEL32.DLL.BaseThreadInitThunk
(00061FE8) ntdll.dll.RtlValidSecurityDescriptor
(00061FB5) ntdll.dll.RtlValidSecurityDescriptor

(008671C9)
(008687A3)
(006F9693)
(006F8E5A)
(00736CEB)
(00771BF7)
(006C8C4D)
(006C3C14)
(00098B63)
(00017482) KERNEL32.DLL.BaseThreadInitThunk
(00061FE8) ntdll.dll.RtlValidSecurityDescriptor
(00061FB5) ntdll.dll.RtlValidSecurityDescriptor
Authentication failed.

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.