diff --git a/hugolib/page_paths.go b/hugolib/page_paths.go
index 0d1b1c363..f842abdd7 100644
--- a/hugolib/page_paths.go
+++ b/hugolib/page_paths.go
@@ -141,6 +141,15 @@ func createTargetPath(d targetPathDescriptor) string {
 
 	isUgly := d.UglyURLs && !d.Type.NoUgly
 
+	// If the page output format's base name is the same as the page base name,
+	// we treat it as an ugly path, i.e.
+	// my-blog-post-1/index.md => my-blog-post-1/index.html
+	// (given the default values for that content file, i.e. no slug set etc.).
+	// This introduces the behaviour from < Hugo 0.20, see issue #3396.
+	if d.BaseName != "" && d.BaseName == d.Type.BaseName {
+		isUgly = true
+	}
+
 	if d.Kind != KindPage && len(d.Sections) > 0 {
 		pagePath = filepath.Join(d.Sections...)
 		needsBase = false
diff --git a/hugolib/page_paths_test.go b/hugolib/page_paths_test.go
index ded8e6997..5f0fa3555 100644
--- a/hugolib/page_paths_test.go
+++ b/hugolib/page_paths_test.go
@@ -62,6 +62,16 @@ func TestPageTargetPath(t *testing.T) {
 								BaseName: "mypage",
 								Sections: []string{"a"},
 								Type:     output.HTMLFormat}, "/a/b/mypage/index.html"},
+
+						{
+							// Issue #3396
+							"HTML page with index as base", targetPathDescriptor{
+								Kind:     KindPage,
+								Dir:      "/a/b",
+								BaseName: "index",
+								Sections: []string{"a"},
+								Type:     output.HTMLFormat}, "/a/b/index.html"},
+
 						{
 							"HTML page with special chars", targetPathDescriptor{
 								Kind:     KindPage,
@@ -139,7 +149,9 @@ func TestPageTargetPath(t *testing.T) {
 						expected := test.expected
 
 						// TODO(bep) simplify
-						if test.d.Kind == KindHome && test.d.Type.Path != "" {
+						if test.d.BaseName == test.d.Type.BaseName {
+
+						} else if test.d.Kind == KindHome && test.d.Type.Path != "" {
 						} else if (!strings.HasPrefix(expected, "/index") || test.d.Addends != "") && test.d.URL == "" && isUgly {
 							expected = strings.Replace(expected,
 								"/"+test.d.Type.BaseName+"."+test.d.Type.MediaType.Suffix,
diff --git a/hugolib/site_test.go b/hugolib/site_test.go
index 1df3c81c7..3868055e9 100644
--- a/hugolib/site_test.go
+++ b/hugolib/site_test.go
@@ -959,11 +959,13 @@ func TestRefLinking(t *testing.T) {
 	}{
 		// Note: There are no magic in the index.md name. This was fixed in Hugo 0.20.
 		// Before that, index.md would wrongly resolve to "/".
-		{"index.md", "", true, "/index/"},
+		// See #3396 -- there is an ambiguity in the examples below, even if they do work.
+		// TODO(bep) better test cases
+		{"index.md", "", true, "/"},
 		{"common.md", "", true, "/level2/common/"},
 		{"3-root.md", "", true, "/level2/level3/3-root/"},
-		{"index.md", "amp", true, "/amp/index/"},
-		{"index.md", "amp", false, "http://auth/amp/index/"},
+		{"index.md", "amp", true, "/amp/"},
+		{"index.md", "amp", false, "http://auth/amp/"},
 	} {
 		if out, err := site.Info.refLink(test.link, currentPage, test.relative, test.outputFormat); err != nil || out != test.expected {
 			t.Errorf("[%d] Expected %s to resolve to (%s), got (%s) - error: %s", i, test.link, test.expected, out, err)
@@ -981,9 +983,11 @@ func TestSourceRelativeLinksing(t *testing.T) {
 
 	okresults := map[string]resultMap{
 		"index.md": map[string]string{
-			"/docs/rootfile.md":             "/rootfile/",
-			"rootfile.md":                   "/rootfile/",
-			"index.md":                      "/index/",
+			"/docs/rootfile.md": "/rootfile/",
+			"rootfile.md":       "/rootfile/",
+			// See #3396 -- this may potentially be ambiguous (i.e. name conflict with home page).
+			// But the user have chosen so. This index.md patterns is more relevant in /sub-folders.
+			"index.md":                      "/",
 			"level2/2-root.md":              "/level2/2-root/",
 			"/docs/level2/2-root.md":        "/level2/2-root/",
 			"level2/level3/3-root.md":       "/level2/level3/3-root/",