The creators of any canonical work are always open to changing it as they go. If they don't have the option to actually go back and alter things in earlier installments, as Lucas did in the film re-releases, they'll just retcon or ignore the bad or problematical ideas from earlier installments and pretend they always happened differently. Canon is a moving target.
It should be noted that this is nothing new. Johnston McCully did the same thing back when he was writing the original ZORRO novels, and I imagine (although I can't quote chapter in verse) that the same applies to DOC SAVAGE, THE SHADOW, TARZAN, THE HARDY BOYS, NANCY DREW, and probably even Sherlock Holmes and Tom Sawyer.
And don't get me started on the continuity lapses and retcons in the old Universal and Hammer monster movies. Or the Godzilla films for the matter. And, you know what, audiences back then didn't seem to mind.
(Maybe because there was no home video or internet?)
As I like to say, continuity is a virtue, but it's not the only virtue or even the most important one. Last time I checked, Zorro is still around . . . .