Error occurred during logging. It's been turned off - System::UStrCat

WinSCP was sitting idle connected to 2 services overnight.

WinSCP 5.7.7

Error message:
Error occurred during logging. It's been turned off.

Invalid access to memory.

Stack trace:
(003B373C) System::UStrCat
(007E08AA) C4799_0
(007E2912) ____ExceptionHandler
(007DF88C) __ExceptionHandler
(0008A61F) ntdll.dll
(00077E7A) ntdll.dll.KiUserExceptionDispatcher
(006CB447) TSessionLog::DoAdd
(006CB5C0) TSessionLog::Add
(006CB16B) TSessionLog::DoAddToParent
(006CB5C0) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006CB799) TSessionLog::AddException
(006CB718) TSessionLog::Add
(006

The problem happens rarely. I cannot reproduce it.

<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 5.19.2

Error message:
Invalid access to memory.

Stack trace:
(0043CA18) System::UStrCat
(00FBC612) C5294_3
(00FBE67A) ____ExceptionHandler
(00FBB434) __ExceptionHandler
(00088F9F) ntdll.dll
(000741F1) ntdll.dll.KiUserExceptionDispatcher
(00D74199) TSessionLog::DoAdd
(00D74310) TSessionLog::Add
(00D73AE3) TSessionLog::DoAddToParent
(00D74310) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D744C5) TSessionLog::AddException
(00D7444B) TSessionLog::Add
(00D7

The problem happens rarely. I cannot reproduce it.