I thought so too, the complete lack of emotion was odd. That flat affect could be a gas lighting technique (Amber has the higher moral ground, as Norma is raising her voice/cursing), or the droll in her voice could be a deliberate tactic to incite Norma to rage (I'm so bored with these allegations..)What was so striking to me about that recording was Amber's very flat affect. It was almost mercenary.
I saw this comment on Karina's video, also possible, though I doubt Amber could overcome her laziness long enough to write a script.
Edit to add Ann appears to be a hardcore hater, if this post is correct. If Ann has been a hater all this time, why release these voice notes now? And why delete them hours later?
Edit again to add the theory was put out (on the Kicking Geese livestream today) that Ann deliberately leaked these messages now. Amber is physically with Becky's family, so the effect of leaking now is maximised, as Amber will get it in the neck from the family. As opposed to Becky, who ironically has no neck..