1 files changed, 11 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index f73b0b90cf..8bed7121a8 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -67,6 +67,7 @@ module ActiveRecord
       def reset
         super
         @target = []
+        @association_ids = nil
       end
 
       def find(*args)
@@ -356,7 +357,10 @@ module ActiveRecord
             transaction do
               add_to_target(build_record(attributes)) do |record|
                 yield(record) if block_given?
-                insert_record(record, true, raise) { @_was_loaded = loaded? }
+                insert_record(record, true, raise) {
+                  @_was_loaded = loaded?
+                  @association_ids = nil
+                }
               end
             end
           end
@@ -429,7 +433,12 @@ module ActiveRecord
           records.each do |record|
             raise_on_type_mismatch!(record)
             add_to_target(record) do
-              result &&= insert_record(record, true, raise) { @_was_loaded = loaded? } unless owner.new_record?
+              unless owner.new_record?
+                result &&= insert_record(record, true, raise) {
+                  @_was_loaded = loaded?
+                  @association_ids = nil
+                }
+              end
             end
           end