The case you might be thinking of is the JBIG2 implementation bug [1, 2] in Xerox photocopiers where the pattern-matching would incorrectly treat certain characters as interchangeable, leading to numbers getting rewritten in spreadsheets.

[1] https://www.bbc.com/news/technology-23588202

[2] https://www.dkriesel.com/en/blog/2013/0810_xerox_investigati...