If there are not a lot of file operations, it is pretty rare. It can happen during development as folks are making changes on the board and then pulling power.
Linux has a setting for how often the flash is committed to reduce the risk, but of course there could be different side effects. You can see a writeup on the topic here, as it is common in all of this type of single board computers
Your smartphone fixes this by making you press the poweroff button before shutting off power.