merchants not always refreshing inventory upon player levelup

hello,

because i diligently purchase salvageable items, i'm always visiting merchants (even from earlier acts) as soon as my character levels up, because that's when i'm told they refresh their inventory.

but sometimes the merchant inventories appear to be the same or very similar after i level up. i haven't paid very close attention, so maybe the new items are rerolls or just lookalikes, but perhaps this is a bug that needs fixing.

let me know if you want me to pay closer attention and try to reproduce the error.

thanks.
-az