DerivedDataCache: Temp file is short! Error

Hello, we can’t seem to figure out why our build process is throwing this warning occasionally.

LogInit: Display: LogDerivedDataCache: Warning: //ddc.local.mylab.net/myGameDDC: Temp file is short //ddc.local.mylab.net/myGameDDC/4/2/2/temp.B9F116DB45530EE789EFE39F9DEBE973!

I’ve verified that it is not a permission issue (Also the error thrown would have mentioned it after looking at the code)

bool bResult;
				{
					bResult = FFileHelper::SaveArrayToFile(Data, *TempFilename, &IFileManager::Get(), FILEWRITE_Silent);
				}
				if (bResult){
....
} else {
					uint32 ErrorCode = FPlatformMisc::GetLastError();
					TCHAR ErrorBuffer[1024];
					FPlatformMisc::GetSystemErrorMessage(ErrorBuffer, 1024, ErrorCode);
					UE_LOG(LogDerivedDataCache, Warning, TEXT("FFileSystemDerivedDataBackend: Could not write temp file %s! Error: %u (%s)"), *TempFilename, ErrorCode, ErrorBuffer);
				}

I’ve verified that we have over 1TB of free space on the drive containing the DDC. For some reason the # of bytes written to the file does not match the # of bytes it should have written.

We are building the game using a windows PC, the DDC is being ran on a linux box. If anyone has any hints or advice on how to debug this issue it would be greatly appreciated. I’m not sure how to proceed besides maybe editing the code to add even more verbose logging?