Integrated Darktrace Syslog with FortiAnalyzer.

I have integrated Darktrace Syslog with FortiAnalyzer. When Darktrace sends logs in JSON format, the log messages are truncated in FortiAnalyzer. However, when I configure Darktrace to send logs in CEF format, the Message field in FortiAnalyzer is empty.

Could you please advise on the cause of this behavior and recommend the appropriate configuration to ensure the complete log message is displayed in FortiAnalyzer?