@John of Japan
To say it is a goof in the KJV is to say it is a goof in Tyndale's Bible & a goof in Martin Luthor's German Bible & they were both before the KJV.
Since Easter existed in the entire N.T. and not just Acts 12:4 before the KJV, it cannot be considered a goof when it represented the Jewish festivity in the Old Testament that we know now as Passover as the Jewish festivity was known in the entire N.T. as Easter back then
Since Passover in English was not known to Luke but pascha in the Greek, then neither was Easter in English or German from pascha was known to Luke.
It's kind of like saying that false charge against the KJV as if KJVers were saying God's words is preserved only in English which the KJVers never said. Indeed, by saying that false charge, you condemn all modern bibles because they are in English too.
So to call Easter a goof in the KJV when it wasn't in the first place is you attacking Tyndale's Bible in English & Martin Luther's bible in German for back then Easter in the N.T. represented what was translated then as Passover in the O.T. back then.
You are just stuck in the modern day usage of it, denying the other usage for Easter as referring to that Jewish festivity back then. And you'd be remiss if you believed that back then, the people did not see Tyndale's Bible nor Martin Luther's Bible as a goof when they knew what they meant too & understood Easter to represent that Jewish festivity in the O.T. .