diff --git a/node_modules/karma/lib/browser.js b/node_modules/karma/lib/browser.js
index aa87957925..2e4f7c5f2f 100644
--- a/node_modules/karma/lib/browser.js
+++ b/node_modules/karma/lib/browser.js
@@ -192,12 +192,14 @@ class Browser {
     if (this.noActivityTimeout) {
       this.clearNoActivityTimeout()
 
-      this.noActivityTimeoutId = this.timer.setTimeout(() => {
-        this.lastResult.totalTimeEnd()
-        this.lastResult.disconnected = true
-        this.disconnect(`, because no message in ${this.noActivityTimeout} ms.`)
-        this.emitter.emit('browser_complete', this)
-      }, this.noActivityTimeout)
+      if(this.state !== 'DISCONNECTED') {
+        this.noActivityTimeoutId = this.timer.setTimeout(() => {
+          this.lastResult.totalTimeEnd()
+          this.lastResult.disconnected = true
+          this.disconnect(`, because no message in ${this.noActivityTimeout} ms.`)
+          this.emitter.emit('browser_complete', this)
+        }, this.noActivityTimeout)
+      }
     }
   }