Custom Master Page Feature on Parent Site automatically getting activated on activating child's master page feature

Question

I've created and deployed a custom master page and kept its scope to be Web because I want to apply to specific sites not the complete site collection. But when I activate feature at a specific site, it automatically gets activated to the parent site and thus each site. This happens only the first time a feature is activated after deploying. There after( After I've manually deactivated that feature from the parent site) it works fine. Please can anyone suggest something so that it gets activated on the specific site only? It's been chewing off my mind for quite sometime now :/

Following is the code I've used on Feature activated method of feature event receiver

      public override void FeatureActivated(SPFeatureReceiverProperties properties)
      {
        using (var web = (SPWeb)properties.Feature.Parent)
        {
            string customUrltoUse = web.ServerRelativeUrl + CustomizedMasterUrl;
            customUrltoUse = customUrltoUse.Replace("//", "/");

            // Store the old Master URL's and Custom Master URL's
            web.AllProperties["OldMasterUrl"] = web.MasterUrl;
            web.AllProperties["OldCustomMasterUrl"] = web.CustomMasterUrl;
            web.AllProperties["__InheritsCustomMasterUrl"] = "False";
            web.AllProperties["__InheritsMasterUrl"] = "False";
            // Assign the Master URL to both properties

            try
            {
                if (web.IsRootWeb)
                {
                    foreach (SPWeb subweb in web.Webs)
                    {
                        if (subweb.WebTemplateId != 50 && subweb.WebTemplateId != 14483)
                        {
                            subweb.MasterUrl = customUrltoUse;
                            subweb.CustomMasterUrl = customUrltoUse;
                            subweb.Update();

                            if (subweb.Webs.Count > 0)
                            {
                                foreach (SPWeb subsubweb in subweb.Webs)
                                {
                                    subsubweb.MasterUrl = customUrltoUse;
                                    subsubweb.CustomMasterUrl = customUrltoUse;
                                    subsubweb.Update();
                                }
                            }
                        }
                    }
                }

                //SPFile uipmasterPage = web.GetFile(web.ServerRelativeUrl + "/_catalogs/masterpage/uipcustom.master");

                //uipmasterPage.Delete();
            }
            catch
            {
            }

            web.MasterUrl = customUrltoUse;
            web.CustomMasterUrl = customUrltoUse;

            web.Update();   }
    }

Answer 1

When deploying Masterpages and Pagelayouts, the feature deploying them should always be SITE scoped as they can only be added to site collection root levels.

Then if you want to control which subsites should use the deployed masterpage (if you do not have Publishing Features activated), you create a new feature, which is WEB scoped, with a FeatureReceiver containing code to set the masterpage for the current web.