fix

packages/svelte/src/internal/client/dom/hydration.js

@@ -62,7 +62,13 @@ function get_hydrate_nodes(node, insert_text = false) {
 			if (data === '[') {
 				depth += 1;
 				will_start = true;
-			} else if (data === ']' && --depth === 0) {
+			} else if (data === ']') {
+				if (!started) {
+					// TODO get rid of this — it exists because each blocks are doubly wrapped
+					return null;
+				}
+
+				if (--depth === 0) {
 					if (insert_text && nodes.length === 0) {
 						var text = empty();
 						nodes.push(text);
@@ -72,6 +78,7 @@ function get_hydrate_nodes(node, insert_text = false) {
 					return nodes;
 				}
 			}
+		}
 
 		if (started) {
 			nodes.push(current_node);