I've seen this happen in enterprise systems integration work, where some data interchange spec is authored as a Word document, and it has tables defining valid string values for certain fields, and Word helpfully replaces plain ascii dashes in the string constants with pretty long dashes, and team A builds their side hand-typing these constants as plain ascii, and team B builds their side by copy-pasting the exact unicode strings out of the Word doc.

Not a hard thing to debug once the issue is noticed, and completely preventable (write specs in plain text).