A new beta was just uploaded that has the ability to format the text tokens to ignore the LaTex characters.
In the drawing command you are using (e.g., Plot, Points, etc) go the Legend name entry box. Click on the right side of a token on the ‘∨’ symbol to see this option. Click to enable.
Then you can have an underscore in the legend without it becoming a subscript.
Hope this helps – we are close to finalizing the next release and trying to avoid major changes but this was something we already were testing, so easy to implement. Would be great if you could test and make sure this works for your use case.