works correct

src/compile/render-dom/Block.ts

@@ -164,7 +164,7 @@ export default class Block {
 
 		if (parent_node) {
 			this.builders.mount.add_line(`@append(${parent_node}, ${name});`);
-			if (parent_node === 'document.head') this.builders.destroy.add_line(`@detach(${name});`);
+			if (parent_node === 'document.head' && !no_detach) this.builders.destroy.add_line(`@detach(${name});`);
 		} else {
 			this.builders.mount.add_line(`@insert(#target, ${name}, anchor);`);
 			if (!no_detach) this.builders.destroy.add_conditional('detaching', `@detach(${name});`);

src/compile/render-dom/wrappers/RawMustacheTag.ts

@@ -21,9 +21,18 @@ export default class RawMustacheTagWrapper extends Tag {
 	render(block: Block, parent_node: string, parent_nodes: string) {
 		const name = this.var;
 
+		const in_head = parent_node === 'document.head';
+		const needs_anchors = !parent_node || in_head;
+
+		// if in head always needs anchors
+		if (in_head) {
+			this.prev = null;
+			this.next = null;
+		}
+
 		// TODO use is_dom_node instead of type === 'Element'?
-		const needs_anchor_before = this.prev ? this.prev.node.type !== 'Element' : !parent_node;
-		const needs_anchor_after = this.next ? this.next.node.type !== 'Element' : !parent_node;
+		const needs_anchor_before = this.prev ? this.prev.node.type !== 'Element' : needs_anchors;
+		const needs_anchor_after = this.next ? this.next.node.type !== 'Element' : needs_anchors;
 
 		const anchor_before = needs_anchor_before
 			? block.get_unique_name(`${name}_before`)
@@ -89,7 +98,7 @@ export default class RawMustacheTagWrapper extends Tag {
 
 		block.builders.mount.add_line(insert(init));
 
-		if (!parent_node) {
+		if (needs_anchors) {
 			block.builders.destroy.add_conditional('detaching', needs_anchor_before
 				? `${detach}\n@detach(${anchor_before});`
 				: detach);
@@ -100,4 +109,4 @@ export default class RawMustacheTagWrapper extends Tag {
 			add_anchor_after();
 		}
 	}
-}
+}