I’ve been saying this for a long time.
Pathological liars lie even when there is no obvious advantage to lying and the lies are super simple to detect or check out.
I have known people like this. It’s a compulsion, they don’t really know they are doing it in many cases and the lies are tiny as well as big ... no distinction for the liar.
I do not know anyone like this.
Of course it would be hard to tell—once I spot a liar I am long gone from their world before they get a chance to repeat.