I just wanted add that I recognized this issue (copying file from one tree to a 64bit-Windows host) with both the stable version 4.53 as well as with the Beta, 5.0.6
As we use WinSCP a lot, we are looking forward for a solution for this. You can contact me any time with questions for details.
Please direct your request for Far-NetBox project:
https://github.com/michaellukashov/Far-NetBox