Timeline Discrepancies? Is the current official description stating that HotD takes place 300 years before GoT a marketing error, considering that S8 supposedly ends in 305 AC, or is HBO retconning the timeline to accomodate their other planned spin-off series? 

I'm more inclined to believe the former since GoT never really cared to properly establish its timeline and that from a marketing perspective, 300 years sounds a lot more interesting than say 177 years.