#399

backend/app/models/post.rb

@@ -253,7 +253,7 @@ class Post < ApplicationRecord
         value.match(
             /\A(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})/ \
             '(?::(\d{2})(?:\.(\d+))?)?' \
-            '(Z|[+-]\d{2}:?\d{2})\z/')
+            '(Z|[+-]\d{2}:?\d{2})?\z/')
     return nil if match.nil?
 
     year = match[1].to_i
@@ -265,16 +265,26 @@ class Post < ApplicationRecord
     fraction = match[7]
     offset = match[8]
     return nil unless valid_original_created_components?(year, month, day, hour, minute, second)
-    return nil unless valid_original_created_offset?(offset)
+    return nil if offset.present? && !(valid_original_created_offset?(offset))
 
-    Time.new(
+    if offset.present?
+      return Time.new(
+          year,
+          month,
+          day,
+          hour,
+          minute,
+          second + Rational(parse_original_created_nanoseconds(fraction), 1_000_000_000),
+          normalise_original_created_offset(offset)).in_time_zone
+    end
+
+    Time.zone.local(
         year,
         month,
         day,
         hour,
         minute,
-        second + Rational(parse_original_created_nanoseconds(fraction), 1_000_000_000),
-        normalise_original_created_offset(offset)).in_time_zone
+        second).change(nsec: parse_original_created_nanoseconds(fraction))
   rescue ArgumentError, TypeError
     nil
   end