PHILADELPHIA — Once again, Andy Reid’s coaching errors overshadowed a weekend’s worth of wonderment. Once again, much of Philadelphia rejoiced. Once again, it’s a sad sight to see. Joe Burrow’s comeback brilliance in an overtime win sent the Bengals to their first Super Bowl since Cris Collinsworth wasn’t obnoxious. Instead, it is Reid’s failure to protect his team’s 18-point lead Sunday that mattered more. It’s the third time in Reid’s nine years with the Chiefs that he has blown a playoff lead of at least 18 points, the latest in a series of exquisite regurgitations. This episode’s key drama…