While I don't know what happened, this looks like the chips arrived, with the type-setters error in evidence and for reason(s) unknown, the chips were put into play and not returned for replacement. Maybe the house did not notice the mistake, or they didn't care, or maybe only the collectors have noticed it.

Remember the faded Chipcos? Even when Chipco offered a complete replacement (at no charge), some casinos opted to just go with the bad ones. Go figure.

However, in my opinion, if one chip was found that had the spelling correct, it would not be an error and most likely would cause all the mispelled ones to be firmly categorized as 'error' chips. But just the same, they would be a common error. I remember when I was a kid I collected postage stamps for a short while. There was a misprint that happened with the Dag Hamershald (I'm sure I spelled that wrong) UN stamp. A collector spotted the error and ordered a large bulk of the stamps. The Post Office saw the error and instead of correcting it, they went ahead and printed more of them that way, so that the error become a common thing and kept the collector value even with the collector value of a non-misprinted version.

But, I do not believe that this thread will resolve a chip collector definition of what an error is.

Jim