Fairly recent, as far as I know; probably no earlier than the 1980s. (This is just a guess based on vague memory.) I’m not even sure it has spread much beyond people whose interest in Latin is specifically linguistic. (For instance I don’t know that there are any pedagogical materials—as opposed to linguistic treatises—that use this spelling, though there might be.)
Spelling Latin with u has always been there (but as a tiny minority of texts). Here are some occurrences of omnia uincit amor over the years: 1603, 1743, 1894, 1974.
If you compare the frequencies of vincit and uincit on Google Ngram viewer, you’ll see that the u spelling has always been present at a low frequency. There doesn’t seem to be any noticeable recent trend (other than the general decline of Latin as a proportion of printed material). I tried a few other Latin words and got similar results.
Fairly recent, as far as I know; probably no earlier than the 1980s. (This is just a guess based on vague memory.) I’m not even sure it has spread much beyond people whose interest in Latin is specifically linguistic. (For instance I don’t know that there are any pedagogical materials—as opposed to linguistic treatises—that use this spelling, though there might be.)
Spelling Latin with u has always been there (but as a tiny minority of texts). Here are some occurrences of omnia uincit amor over the years: 1603, 1743, 1894, 1974.
If you compare the frequencies of vincit and uincit on Google Ngram viewer, you’ll see that the u spelling has always been present at a low frequency. There doesn’t seem to be any noticeable recent trend (other than the general decline of Latin as a proportion of printed material). I tried a few other Latin words and got similar results.