How to fix WinSCP hanging at the very end of a transfer

I am trying to upload some larger in size binary type files (order 10^8 bytes) using WinSCP and somewhere around 96->100% I see it timing out. Now in some cases, it seems that the entire file is being successfully transmitted and is usable even though it hangs. I try to do recoect and resume and start over, but none of these will lead to a transfer of the whole file without this timeout.

I see at the same time smaller text files I am transferring have no problem.

What might be causing this hang at the end and how might it be resolved?