diff --git a/routers/web/repo/view_file.go b/routers/web/repo/view_file.go
index f8a7c254ab..ea92f07d5b 100644
--- a/routers/web/repo/view_file.go
+++ b/routers/web/repo/view_file.go
@@ -254,6 +254,16 @@ func prepareFileView(ctx *context.Context, entry *git.TreeEntry) {
 	case fInfo.blobOrLfsSize >= setting.UI.MaxDisplayFileSize:
 		ctx.Data["IsFileTooLarge"] = true
 	case handleFileViewRenderHTML(ctx, fInfo):
+		// ALL debug logs and template data are correct, but the template renders source.
+		// FORCE iframe rendering: override FileContent so template skips source view.
+		ctx.Data["IsImageFile"] = false
+		ctx.Data["IsVideoFile"] = false
+		ctx.Data["IsAudioFile"] = false
+		// Clear any FileContent that might have leaked
+		delete(ctx.Data, "FileContent")
+		delete(ctx.Data, "RenderAsMarkup")
+		delete(ctx.Data, "IsPlainText")
+		delete(ctx.Data, "IsDisplayingSource")
 	case handleFileViewRenderMarkup(ctx, buf, contentReader):
 	case handleFileViewRenderSource(ctx, attrs, fInfo, contentReader):
 		// it also sets ctx.Data["FileContent"] and more