'sawn' is losing ground to 'sawed'. This is the way of language. The "new" rule [that's been around for centuries] that ENLs have in their brain is "the past tense is made by adding "ed". Irregular verbs, though still quite individually strong, are fighting a losing battle.
Results 1 - 10 of about 655 English pages for "have sawn".
Results 1 - 10 of about 9,850 English pages for "have sawed".
I always used "sawn", maybe it's because I'm a Britisher, but sawn always feels more natural to me than sawed, I always the "-N" ending on past participles when applicable, because, as I said, they feel more natural to me.
Also the answers are a bit strange, they start with "See", then go to "Saw" (which is OK), but then goes to "Sawn"/"Sawed", the Saw that's the past tense version of "See" is different from the "Saw" that "Sawn" and "Sawed" come from.