To be fair this was Excell 25 years ago, may no longer be true. One of the other bugs (the Quark/ATM one) was also because of the programmers were worried abou

To be fair this was Excell 25 years ago, may no longer be true. One of the other bugs (the Quark/ATM one) was also because of the programmers were worried about writing over stuff that hadn't been completely erased, the Quark guys wrote a string with 2 spaces at the end through a box that masked the end of the string, the ATM font renderer saw it couldn't fit the text so it split it in half and tried again so it drew N/2 N/4 N/8 ... strings. It spent all it's time in the 68k's multiply instructions figuring out how wide the strings (and substrings) were, our fancy 24-bit character rendering hardware was an afterthought