diff --git a/app/controllers/composer_controller.rb b/app/controllers/composer_controller.rb
index d87441a5615..d8bc8625186 100644
--- a/app/controllers/composer_controller.rb
+++ b/app/controllers/composer_controller.rb
@@ -65,8 +65,12 @@ class ComposerController < ApplicationController
                 .count
 
             if notified_count > 0
-              group_reasons[group.name] = :some_not_allowed
-              serialized_group[:notified_count] = notified_count
+              if notified_count == group.user_count
+                group_reasons.delete(group.name)
+              else
+                group_reasons[group.name] = :some_not_allowed
+                serialized_group[:notified_count] = notified_count
+              end
             end
           end
 
diff --git a/spec/requests/composer_controller_spec.rb b/spec/requests/composer_controller_spec.rb
index 76297223d5c..3e85ca1098c 100644
--- a/spec/requests/composer_controller_spec.rb
+++ b/spec/requests/composer_controller_spec.rb
@@ -185,7 +185,6 @@ RSpec.describe ComposerController do
         other_group = Fabricate(:group, mentionable_level: Group::ALIAS_LEVELS[:everyone])
         other_group.add(allowed_user)
         other_group.add(user)
-        other_group.add(Fabricate(:user))
 
         # Trying to mention other_group which has not been invited, but two of
         # its members have been (allowed_user directly and user via group).
@@ -193,6 +192,15 @@ RSpec.describe ComposerController do
 
         expect(response.status).to eq(200)
 
+        expect(response.parsed_body["groups"]).to eq(other_group.name => { "user_count" => 2 })
+        expect(response.parsed_body["group_reasons"]).to be_empty
+
+        other_group.add(Fabricate(:user))
+
+        get "/composer/mentions.json", params: { names: [other_group.name], topic_id: topic.id }
+
+        expect(response.status).to eq(200)
+
         expect(response.parsed_body["groups"]).to eq(
           other_group.name => {
             "user_count" => 3,