I am also on latest build (2938-) and works for me.


Are you having the problem only inside queries, or do you have them in form grids as well?
Are there custom javascripts running in the background messing it up for you?
Database table encoding issues?
You did use "Plain text" as calculation result like the image above? (make sure this option is not hidden due to window height)
You are sure you only included plain text fields when concatenating? If number, it might treat it as addition.
Just brainstorming here.