I disagree that it's an automatic red flag. 8 hours? Yeah that's too long. But I would rather do a 2 hour take-home project than a 2 hour whiteboard coding interview.
Edit to add: as far as getting paid, nobody expects to get paid for an onsite interview so I wouldn't expect to get paid for a take home project either. As long as it takes the same amount of time that the coding portion of an onsite interview reasonably would, that is.
Edit to add: as far as getting paid, nobody expects to get paid for an onsite interview so I wouldn't expect to get paid for a take home project either. As long as it takes the same amount of time that the coding portion of an onsite interview reasonably would, that is.