diff --git a/common/hmaps/params.go b/common/hmaps/params.go
index a67a45ca8..d85287424 100644
--- a/common/hmaps/params.go
+++ b/common/hmaps/params.go
@@ -120,6 +120,14 @@ func (p Params) merge(ps ParamsMergeStrategy, pp Params) {
 			if vvv, ok := vv.(Params); ok {
 				if pv, ok := v.(Params); ok {
 					vvv.merge(ms, pv)
+				} else if vvv.IsZero() {
+					// The existing value is an empty Params (just merge metadata)
+					// and the incoming value is a non-Params type (e.g. a slice).
+					// If the user has set an explicit non-none merge strategy,
+					// honor it by using the incoming value.
+					if s, found := vvv.GetMergeStrategy(); found && s != ParamsMergeStrategyNone {
+						p[k] = v
+					}
 				}
 			}
 		} else if !noUpdate {
diff --git a/hugolib/cascade_test.go b/hugolib/cascade_test.go
index fa73c511d..783f86c19 100644
--- a/hugolib/cascade_test.go
+++ b/hugolib/cascade_test.go
@@ -544,6 +544,33 @@ cascade:
 	b.AssertFileExists("public/s2/p3/index.html", false)
 }
 
+// Issue 13869
+func TestCascadeSliceFromModule13869(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+disableKinds = ['page','rss','section','sitemap','taxonomy','term']
+theme = 'foo'
+[cascade]
+_merge = 'deep'
+-- content/_index.md --
+---
+title: home
+---
+-- layouts/home.html --
+color: {{ .Params.color }}
+-- themes/foo/hugo.toml --
+[[cascade]]
+[cascade.params]
+color = 'red'
+`
+
+	b := Test(t, files)
+
+	b.AssertFileContent("public/index.html", "color: red")
+}
+
 // Issue 14848
 func TestCascadeParamsLangIssue14848(t *testing.T) {
 	t.Parallel()
diff --git a/hugolib/page_permalink_test.go b/hugolib/page_permalink_test.go
index 66281b5b5..c2fe8f089 100644
--- a/hugolib/page_permalink_test.go
+++ b/hugolib/page_permalink_test.go
@@ -75,7 +75,7 @@ canonifyURLs = %t
 ---
 title: Page
 slug: %q
-url: %q	
+url: %q
 output: ["HTML"]
 ---
 `, test.base, test.uglyURLs, test.canonifyURLs, test.file, test.slug, test.url)
@@ -173,3 +173,31 @@ Some content.
 	b.AssertFileContent("public/myblog/p2/index.html", "Single: A page|Hello|en|RelPermalink: /myblog/p2/|Permalink: https://example.com/myblog/p2/|")
 	b.AssertFileContent("public/myblog/p3/index.html", "Single: A page|Hello|en|RelPermalink: /myblog/p3/|Permalink: https://example.com/myblog/p3/|")
 }
+
+// Issue 13869
+func TestPermalinksSliceFromModule13869(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- hugo.toml --
+disableKinds = ['home','rss','section','sitemap','taxonomy','term']
+theme = 'foo'
+[permalinks]
+_merge = 'deep'
+-- content/books/my-book.md --
+---
+title: My Book
+---
+-- layouts/page.html --
+RelPermalink: {{ .RelPermalink }}
+-- themes/foo/hugo.toml --
+[[permalinks]]
+pattern = '/shelf/:slug/'
+[permalinks.target]
+path = '/books/**'
+`
+
+	b := Test(t, files)
+
+	b.AssertFileContent("public/shelf/my-book/index.html", "RelPermalink: /shelf/my-book/")
+}