User blog comment:Eclectica737/Black Bolt's physical age/@comment-16461120-20190827024303/@comment-16461120-20190904004607

Your confusion lies in the fact that dates in the Modern Age are virtually always to be considered Topical References, so Steve's birthday, which happened before the Modern Age, remains unchanged as a factual reference; meanwhile, his time in the ice perpetually lengthens relative to publication dates because he awoke at a point in time within the Modern Age, that is to say, the Sliding Timescale essentially creates that which is topical in perpetuity.