I think this return is needed to prevent sending the i18n query results twice and crashing the server.

app/views/i18n/I18NHomeView.coffee

@@ -13,30 +13,30 @@ PAGE_SIZE = 100
 module.exports = class I18NHomeView extends RootView
   id: "i18n-home-view"
   template: template
-  
+
   events:
     'change #language-select': 'onLanguageSelectChanged'
 
   constructor: (options) ->
     super(options)
     @selectedLanguage = me.get('preferredLanguage', true)
-    
+
-    #- 
+    #-
     @aggregateModels = new Backbone.Collection()
     project = ['name', 'components.original', 'i18nCoverage', 'slug']
-    
+
     @thangTypes = new CocoCollection([], { url: '/db/thang.type?view=i18n-coverage', project: project, model: ThangType })
     @components = new CocoCollection([], { url: '/db/level.component?view=i18n-coverage', project: project, model: LevelComponent })
     @levels = new CocoCollection([], { url: '/db/level?view=i18n-coverage', project: project, model: Level })
     @achievements = new CocoCollection([], { url: '/db/achievement?view=i18n-coverage', project: project, model: Achievement })
-    
+
     for c in [@thangTypes, @components, @levels, @achievements]
       c.skip = 0
       c.fetch({data: {skip: 0, limit: PAGE_SIZE}, cache:false})
       @supermodel.loadCollection(c, 'documents')
       @listenTo c, 'sync', @onCollectionSynced
 
-    
+
   onCollectionSynced: (collection) ->
     for model in collection.models
       model.i18nURLBase = switch model.constructor.className
@@ -51,7 +51,7 @@ module.exports = class I18NHomeView extends RootView
     if getMore
       collection.skip += PAGE_SIZE
       collection.fetch({data: {skip: collection.skip, limit: PAGE_SIZE}})
-  
+
   getRenderData: ->
     c = super()
     @updateCoverage()
@@ -59,25 +59,25 @@ module.exports = class I18NHomeView extends RootView
     c.selectedLanguage = @selectedLanguage
     c.collection = @aggregateModels
     c
-    
+
   updateCoverage: ->
     selectedBase = @selectedLanguage[..2]
     relatedLanguages = (l for l in languages when l.startsWith(selectedBase) and l isnt @selectedLanguage)
     for model in @aggregateModels.models
       @updateCoverageForModel(model, relatedLanguages)
       model.generallyCovered = true if @selectedLanguage.startsWith 'en'
-      
+
   updateCoverageForModel: (model, relatedLanguages) ->
     model.specificallyCovered = true
     model.generallyCovered = true
     coverage = model.get('i18nCoverage')
-    
+
     if @selectedLanguage not in coverage
       model.specificallyCovered = false
       if not _.any((l in coverage for l in relatedLanguages))
         model.generallyCovered = false
         return
-        
+
   afterRender: ->
     super()
     @addLanguagesToSelect(@$el.find('#language-select'), @selectedLanguage)

server/commons/Handler.coffee

@@ -33,14 +33,14 @@ module.exports = class Handler
   hasAccess: (req) -> true
   hasAccessToDocument: (req, document, method=null) ->
     return true if req.user?.isAdmin()
-    
+
     if @modelClass.schema.uses_coco_translation_coverage and (method or req.method).toLowerCase() is 'put'
       return true if @isJustFillingTranslations(req, document)
-    
+
     if @modelClass.schema.uses_coco_permissions
       return document.hasPermissionsForMethod?(req.user, method or req.method)
     return true
-    
+
   isJustFillingTranslations: (req, document) ->
     differ = deltasLib.makeJSONDiffer()
     omissions = ['original'].concat(deltasLib.DOC_SKIP_PATHS)
@@ -121,6 +121,7 @@ module.exports = class Handler
         return @sendDatabaseError(res, err) if err
         documents = (@formatEntity(req, doc) for doc in documents)
         @sendSuccess(res, documents)
+      return
 
     specialParameters = ['term', 'project', 'conditions']