We have icons that represent specific individual collections. like Icon_Outliner_Collection for a default (uncolored) collection, and Icon_Collection_color_x for ones with colors. For "collections" as a general thing though we have icon_group. Sometimes we confuse the two, for example the list of tabs to show in Properties uses a different icon than the actual category icon. This PR fixes the complaint by using the correct icon for each of these purposes. Pull Request: https://projects.blender.org/blender/blender/pulls/147652