I am trying to create a dotaccentcmb.sc and Glyphs automatically renames it to dotaccentcomb.sc. I think this renaming was not happening few weeks ago. Is this a new feature? This type of automatic stuff makes it harder than it already is to work with 3rd party tools.
That behavior is not new; Glyphs will convert glyph names to be consistent with its naming scheme. You can select the Use Custom Naming option in Font Info to use your own names.