Ascension vs. Quo Vadis, Acts 25:19

I understand that, according to Christian tradition, the Messiah ascended into heaven after his resurrection. Scholars and sources would seem to place the ascension between 3 days and 18 months after the resurrection.

However, the Messiah appeared to Paul on the road to Damascus several years after the resurrection (Acts ). And Paul is reported to have still held that the Messiah was alive in 59/60 CE when he was imprisoned in Jerusalem (Acts 25:19). And, according to the enduring Quo Vadis tradition, the Messiah appeared to Peter outside of Rome in 67 CE when Peter and Paul were executed by Nero.

So, the Messiah kept appearing to people, who held that he was quite alive, for at least 30 years after the resurrection. But, how can that be if the Messiah was already ascended into heaven at that point?