Error reading SessionImages.PngImages: Error reading TPngImageCollectionItem.PngImage.Data: This

<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
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WinSCP 5.9

Error message:
Error reading SessionImages.PngImages: Error reading TPngImageCollectionItem.PngImage.Data: This "Portable Network Graphics" image is not valid because it contains invalid pieces of data (crc error)

Trace de la pile :
(00363487) System::Classes::_17687
(003636C1) System::Classes::TReader::ReadProperty
(00362779) System::Classes::TReader::ReadCollection
(00363B2F) System::Classes::TReader::ReadPropValue
(00363662) System::Classes::TReader::ReadProperty
(00362EB5) System::Classes::TReader::ReadDataInner
(00362E97) System::Classes::TReader::ReadData
(00370A59) System::Classes::TComponent::ReadState
(00362F29) System::Classes::TReader::ReadDataInner
(00362E68) System::Classes::TReader::ReadData
(00370A59) System::Classes::TComponent::ReadState
(0035DD0E) System::Classes::TStream::ReadComponent
(00353753) System::Classes::_17089
(003550A7) System::Classes::_17116
(00355135) System::Classes::InitInheritedComponent
(00372060) System::Classes::TDataModule::TDataModule
(0080C3C8) TGlyphsModule::TGlyphsModule
(000D59A0) Execute
(000024A8) wWinMain
(008601A5) C4941_0
(00062646) ntdll.dll
(00062616) ntdll.dll

(00363487) System::Classes::_17687
(003636C1) System::Classes::TReader::ReadProperty
(00362EB5) System::Classes::TReader::ReadDataInner
(00362E97) System::Classes::TReader::ReadData
(00370A59) System::Classes::TComponent::ReadState
(00362F29) System::Classes:

The problem happens rarely. I cannot reproduce it.