I have created a script below that will simulate exactly what I'm experiencing.
If I redirect the script's output to a file and monitor that with the following sourcetype in props.conf, it event breaks all OK.
If I use exactly the same sourcetype for the input/script everything works, however, I never get to see Fan 2!?
I've tried various types of LINEBREAK/LINE MERGE/MAXEVENTS to get it work with no success, although, I must have missed the magic combination...