diff --git a/packages/buttplug/src/utils/ButtplugMessageSorter.ts b/packages/buttplug/src/utils/ButtplugMessageSorter.ts
index ba4cc10..d9deb42 100644
--- a/packages/buttplug/src/utils/ButtplugMessageSorter.ts
+++ b/packages/buttplug/src/utils/ButtplugMessageSorter.ts
@@ -49,6 +49,7 @@ export class ButtplugMessageSorter {
       let id = Messages.msgId(x);
       if (id !== Messages.SYSTEM_MESSAGE_ID && this._waitingMsgs.has(id)) {
         const [res, rej] = this._waitingMsgs.get(id)!;
+        this._waitingMsgs.delete(id);
         // If we've gotten back an error, reject the related promise using a
         // ButtplugException derived type.
         if (x.Error !== undefined) {
diff --git a/packages/frontend/src/routes/play/+page.svelte b/packages/frontend/src/routes/play/+page.svelte
index 2cf8fe8..8f921ca 100644
--- a/packages/frontend/src/routes/play/+page.svelte
+++ b/packages/frontend/src/routes/play/+page.svelte
@@ -63,10 +63,11 @@ async function onDeviceAdded(dev: ButtplugClientDevice) {
 	const device = convertDevice(dev);
 	devices.push(device);
 
-	// Try to read battery level
+	// Try to read battery level — access through the reactive array so Svelte detects the mutation
+	const idx = devices.length - 1;
 	if (device.hasBattery) {
 		try {
-			device.batteryLevel = await dev.battery();
+			devices[idx].batteryLevel = await dev.battery();
 		} catch (e) {
 			console.warn(`Failed to read battery for ${dev.name}:`, e);
 		}