diff --git a/plugins/player_sync/instance.ts b/plugins/player_sync/instance.ts
index 30ed0223..4c185527 100644
--- a/plugins/player_sync/instance.ts
+++ b/plugins/player_sync/instance.ts
@@ -87,6 +87,22 @@ export function recipeNotificationDelta(stored: string[], current: string[]): Re
 	return delta;
 }
 
+/**
+ * Decode a list of cleared recipe names, Factorio serializes an empty list as {}
+ * @param encoded - Encoded JSON list of recipe names
+ * @returns the recipe names
+ */
+async function decodeRecipeNames(encoded: string): Promise<string[]> {
+	const names = JSON.parse(await decodeLuaString(encoded));
+	if (Array.isArray(names)) {
+		return names;
+	}
+	if (names !== null && typeof names === "object" && Object.keys(names).length === 0) {
+		return [];
+	}
+	throw new Error(`Expected a list of recipe names, got ${JSON.stringify(names)}`);
+}
+
 /**
  * Replace the stored recipe notifications with the difference from the
  * current state on the instance to reduce the amount of data sent to Lua.
@@ -101,9 +117,9 @@ export async function applyRecipeNotificationDelta(
 		return;
 	}
 	try {
-		const stored = JSON.parse(await decodeLuaString(playerData.recipe_notifications));
+		const stored = await decodeRecipeNames(playerData.recipe_notifications);
 		const delta: RecipeNotificationDelta = current
-			? recipeNotificationDelta(stored, JSON.parse(await decodeLuaString(current)))
+			? recipeNotificationDelta(stored, await decodeRecipeNames(current))
 			: { ...recipeNotificationDelta(stored, []), full: true };
 		playerData.recipe_notifications = await encodeLuaString(JSON.stringify(delta));
 	} catch (err: any) {
diff --git a/plugins/player_sync/test/instance.js b/plugins/player_sync/test/instance.js
index 12209271..67132ce6 100644
--- a/plugins/player_sync/test/instance.js
+++ b/plugins/player_sync/test/instance.js
@@ -64,6 +64,29 @@ describe("player_sync", function() {
 			await apply(playerData, undefined);
 			assert.deepEqual(await decode(playerData.recipe_notifications), { full: true });
 		});
+		// helpers.table_to_json in Factorio encodes an empty list as {}
+		it("should treat an empty current list encoded as {} as empty", async function() {
+			const playerData = { name: "test", recipe_notifications: await encode(["a", "b"]) };
+			await apply(playerData, await encode({}));
+			assert.deepEqual(await decode(playerData.recipe_notifications), { add: ["a", "b"] });
+		});
+		it("should treat an empty stored list encoded as {} as empty", async function() {
+			const playerData = { name: "test", recipe_notifications: await encode({}) };
+			await apply(playerData, await encode(["a"]));
+			assert.deepEqual(await decode(playerData.recipe_notifications), { remove: ["a"] });
+		});
+		it("should mark an empty stored list encoded as {} full without a current list", async function() {
+			const playerData = { name: "test", recipe_notifications: await encode({}) };
+			await apply(playerData, undefined);
+			assert.deepEqual(await decode(playerData.recipe_notifications), { full: true });
+		});
+		it("should drop the field when the list is a non-empty object", async function() {
+			const playerData = { name: "test", recipe_notifications: await encode({ a: 1 }) };
+			const count = warnings.length;
+			await apply(playerData, await encode(["a"]));
+			assert.equal(playerData.recipe_notifications, undefined);
+			assert.equal(warnings.length, count + 1);
+		});
 		it("should do nothing without stored notifications", async function() {
 			const playerData = { name: "test" };
 			await apply(playerData, await encode(["a"]));
@@ -71,9 +94,10 @@ describe("player_sync", function() {
 		});
 		it("should drop the field on invalid input", async function() {
 			const playerData = { name: "test", recipe_notifications: "not base64 zlib" };
+			const count = warnings.length;
 			await apply(playerData, await encode(["a"]));
 			assert.equal(playerData.recipe_notifications, undefined);
-			assert.equal(warnings.length, 1);
+			assert.equal(warnings.length, count + 1);
 		});
 	});