Validation issue

[akovia]

Hello and thank you for these wonderful tools.

I was attempting to use this code to help validate and fix a large quantity of barcodes, but I've run into an issue I can't figure out.

I had a string of sequential barcodes that were all missing check digits, but one gives and invalid size message instead of an invalid check digit message.

79996740538 <- " has an invalid check digit."
79996740539 <- " is not a valid barcode size."
79996740540 <- " has an invalid check digit."

Am I possibly not understanding something?
Thank you for any possible help.