diff --git a/packages/node-sdk/package.json b/packages/node-sdk/package.json
index 075186fd..b4dec0ee 100644
--- a/packages/node-sdk/package.json
+++ b/packages/node-sdk/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@bucketco/node-sdk",
-  "version": "1.6.2",
+  "version": "1.6.3",
   "license": "MIT",
   "repository": {
     "type": "git",
diff --git a/packages/node-sdk/src/batch-buffer.ts b/packages/node-sdk/src/batch-buffer.ts
index 2407bc9d..0435a509 100644
--- a/packages/node-sdk/src/batch-buffer.ts
+++ b/packages/node-sdk/src/batch-buffer.ts
@@ -69,19 +69,20 @@ export default class BatchBuffer<T> {
       return;
     }
 
+    const flushingBuffer = this.buffer;
+    this.buffer = [];
+
     try {
-      await this.flushHandler(this.buffer);
+      await this.flushHandler(flushingBuffer);
 
       this.logger?.info("flushed buffered items", {
-        count: this.buffer.length,
+        count: flushingBuffer.length,
       });
     } catch (error) {
       this.logger?.error("flush of buffered items failed; discarding items", {
         error,
-        count: this.buffer.length,
+        count: flushingBuffer.length,
       });
     }
-
-    this.buffer = [];
   }
 }
diff --git a/packages/node-sdk/test/batch-buffer.test.ts b/packages/node-sdk/test/batch-buffer.test.ts
index d6cd2461..e02100ff 100644
--- a/packages/node-sdk/test/batch-buffer.test.ts
+++ b/packages/node-sdk/test/batch-buffer.test.ts
@@ -147,6 +147,22 @@ describe("BatchBuffer", () => {
       );
     });
 
+    it("calling flush simultaneously should only flush data once", async () => {
+      let itemsFlushed = 0;
+      const buffer = new BatchBuffer({
+        flushHandler: async (items) => {
+          itemsFlushed += items.length;
+          await new Promise((resolve) => setTimeout(resolve, 100));
+          mockFlushHandler();
+        },
+        logger: mockLogger,
+      });
+
+      await buffer.add("item1");
+      await Promise.all([buffer.flush(), buffer.flush()]);
+      expect(itemsFlushed).toBe(1);
+    });
+
     it("should flush buffer", async () => {
       const buffer = new BatchBuffer({
         flushHandler: mockFlushHandler,