The HW error numbers are okay for 6k shares. If you lower the intensity setting another digit, you'll probably eliminate HW errors, but it'd probably cost way more in hashrate than it's worth.
There's a decent chance the pool doubled difficulty. It reduces their server load while having minimal impact on users, since when difficulty is doubled, shares' weight is doubled. Is your payout <1/2 what it was?
Yes, for today i haven't cashed out yet but i made 6700 instead of 13000