A translation style guide I read through issues the following recommendation (paraphrased):
Il ne faut pas employer « s'en venir » dans le sens de « devenir ».
Elle s'en vient folle.Elle devient folle.
There are a few recommendations in this guide that make me wonder: are they addressing absurd calques from other languages the translators on their rosters speak, or are these discouraged alternatives actually courant in the langue populaire ?
If I listen as I walk down the streets of a Francophone city, will I hear « Il s'en vient + adjectif » ?
(This is not a question about devenir, which I know is correct.)