That type of joint is called a basic scarf. No, it’s definitely NOT acceptable.
FYI, correction requires installation of gussets by a qualified contractor, gussets being strips of 3/4" plywood ripped to the rafter dimension and glued and nailed to both sides of the rafter for at least the length of the joint, but don’t you specify the correction.
Recommend correction by a qualified contractor or by a SE if you’re worried about liability, but it’s a relatively simple fix unless there’s more than just one.