There was no "official" celebration of the date of Jesus' resurrection in Luke's day, & if there had been, neither Herod nor the Jews woulda observed it.
And clearly, the AV makers knew Easter from passover, recognizing Easter as one of the 2 holiest days of the year, along with Christmas. They added an "Easter-Finder" to the extratextual material of the AV 1611. And the word 'passover' had come into general use.
The word 'pascha' appears 29 times in the NT Greek. It was rendered 'passover' 28 of those times. There was no good reason for the one 'Easter' rendering, except that somebody goofed.