Invalid access to memory

Using SSH Proxy (telnet command).
F5 copy 2 files to local directory leads to those copies timing out on "Connecting". When clicking "Abort" countdown the message box "Invalid access to memory" pops up.

WinSCP 5.9.3

Error message:
Invalid access to memory.

Stack trace:
(00615939)
(00866422)
(0086848A)
(00865244)
(000624F6) ntdll.dll
(0000F13E) ntdll.dll.KiUserExceptionDispatcher
(0060F2EF)
(0064943A)
(006492E6)
(006FECF3)
(006FF239)
(0076EEFF)
(0008EE20)
(00016C9F)
(0003CF87)
(0003CF44)
(00373100)
(000152F7) USER32.dll
(00015D35) USER32.dll
(000167BF) USER32.dll
(00016885) USER32.dll.DispatchMessageW

(00866A8D)
(00868067)
(0008EE65)
(00016C9F)
(0003CF87)
(0003CF44)
(00373100)
(000152F7) USER32.dll
(00015D35) USER32.dll
(000167BF) USER32.dll
(00016885) USER32.dll.DispatchMessageW

Status: unknown_rel_addr

The problem happens rarely. I cannot reproduce it.