diff --git a/lib/community-sync.ts b/lib/community-sync.ts
index 25f6d88..31460af 100644
--- a/lib/community-sync.ts
+++ b/lib/community-sync.ts
@@ -492,7 +492,7 @@ export class CommunitySync extends EventTarget {
 
 		this.#doc = Automerge.change(this.#doc, `Update shape ${shape.id}`, (doc) => {
 			if (!doc.shapes) doc.shapes = {};
-			doc.shapes[shape.id] = shapeData;
+			doc.shapes[shape.id] = JSON.parse(JSON.stringify(shapeData));
 		});
 
 		this.#scheduleSave();
@@ -518,7 +518,9 @@ export class CommunitySync extends EventTarget {
 		// Merge all extra properties from toJSON
 		for (const [key, value] of Object.entries(json)) {
 			if (!(key in data)) {
-				data[key] = value;
+				data[key] = typeof value === 'object' && value !== null
+					? JSON.parse(JSON.stringify(value))
+					: value;
 			}
 		}