The formatting rules in math regions are applied only after evaluation. Thus you can't use regions with just expressions or single names to be formatted correctly. This is particularly annoying if you use boolean = for inactive equations (for documentation purposes) or if you use single names for annotation of images.
Evaluating the region and deleting the result afterwards seems to solve the problem, however, the format is lost after reloading the file (browser refresh).
Another, more persistant trick, which works for undefined names only, is to symbolically evaluate them and then suppressing the input display in the context menu.
All this applies to both SMath in the cloud and build 6528 executables.