I understood that 1/2 converts to 2-Jan (or 1-Feb depending on settings). That is desired behaviour. If you want the string 1/2 you need to use an apostrophe.

I understood that 1/2 converts to 2-Jan (or 1-Feb depending on settings). That is desired behaviour. If you want the string 1/2 you need to use an apostrophe. If you want the fraction one half you need to use an equals sign. Both of these are vastly less likely to be what a user wants than the date interpretation, so it makes sense for that to be the default.