Thanks Peter, for posting your findings. It sounds like the inf value associated with flow sensor may be the culprit. I can talk to Samer to quickly get the UI updated to avoid this issue, and in the next firmware prevent such inf values from being written to the log.
By the way, OS 3.0 does not have a built-in SD card, instead, it write log files to its internal flash memory space. So no SD card necessary.