diff --git a/app/views/dashboard/home.atom.builder b/app/views/dashboard/home.atom.builder
index 6949c2e0c..3b9c4ce23 100644
--- a/app/views/dashboard/home.atom.builder
+++ b/app/views/dashboard/home.atom.builder
@@ -7,7 +7,6 @@ atom_feed do |feed|
   @versions.each do |version|
     feed.entry(version, url: version_url(version.to_param)) do |entry|
       entry.title "#{version.project.name} - #{version.number}"
-      entry.published Time.at(version.published_at).rfc822
       entry.content "", type: "html"
       entry.author do |author|
         author.name("Libraries.io")
diff --git a/app/views/projects/tags.atom.builder b/app/views/projects/tags.atom.builder
index 8662042e5..4ff29a120 100644
--- a/app/views/projects/tags.atom.builder
+++ b/app/views/projects/tags.atom.builder
@@ -7,7 +7,6 @@ atom_feed do |feed|
   @tags.each do |tag|
     feed.entry(tag, url: version_url(@project.to_param.merge(number: tag.name))) do |entry|
       entry.title(tag.number)
-      entry.published Time.at(tag.published_at).rfc822
       entry.content "", type: "html"
       entry.author do |author|
         author.name("Libraries.io")
diff --git a/app/views/projects/versions.atom.builder b/app/views/projects/versions.atom.builder
index c07f17095..4c852d7f2 100644
--- a/app/views/projects/versions.atom.builder
+++ b/app/views/projects/versions.atom.builder
@@ -7,7 +7,6 @@ atom_feed do |feed|
   @versions.each do |version|
     feed.entry(version, url: version_url(version.to_param)) do |entry|
       entry.title(version.number)
-      entry.published Time.at(version.published_at).rfc822
       entry.content "", type: "html"
       entry.author do |author|
         author.name("Libraries.io")
diff --git a/spec/requests/projects_versions_atom_spec.rb b/spec/requests/projects_versions_atom_spec.rb
new file mode 100644
index 000000000..2b447e31e
--- /dev/null
+++ b/spec/requests/projects_versions_atom_spec.rb
@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe "Projects versions Atom feed", type: :request do
+  let!(:project) { create(:project, platform: "NPM", name: "example-package") }
+  let!(:version1) { create(:version, project: project, number: "1.0.0", published_at: 2.days.ago) }
+  let!(:version2) { create(:version, project: project, number: "1.1.0", published_at: 1.day.ago) }
+
+  it "renders RFC3339 <published> once per entry" do
+    visit project_versions_path(project.to_param.merge(format: :atom))
+
+    # Find all <published> elements
+    published_nodes = Nokogiri::XML(page.body).xpath("//xmlns:entry/xmlns:published")
+    expect(published_nodes.length).to eq(2)
+
+    # RFC3339 basic check: YYYY-MM-DDTHH:MM:SSZ
+    rfc3339_regex = /\A\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z\z/
+    published_nodes.each do |node|
+      expect(node.text).to match(rfc3339_regex)
+    end
+  end
+end