diff --git a/lib/session/call-session.js b/lib/session/call-session.js
index c3ec5b45..57eadc4f 100644
--- a/lib/session/call-session.js
+++ b/lib/session/call-session.js
@@ -239,10 +239,10 @@ class CallSession extends Emitter {
       const t = normalizeJambones(this.logger, [gather]);
       this.backgroundGatherTask = makeTask(this.logger, t[0]);
       this.backgroundGatherTask
-        .on('dtmf', this._clearTasks.bind(this))
-        .on('vad', this._clearTasks.bind(this))
-        .on('transcription', this._clearTasks.bind(this))
-        .on('timeout', this._clearTasks.bind(this));
+        .once('dtmf', this._clearTasks.bind(this))
+        .once('vad', this._clearTasks.bind(this))
+        .once('transcription', this._clearTasks.bind(this))
+        .once('timeout', this._clearTasks.bind(this));
       this.logger.info({gather}, 'CallSession:enableBotMode - starting background gather');
       const resources = await this._evaluatePreconditions(this.backgroundGatherTask);
       const {span, ctx} = this.rootSpan.startChildSpan(`background-gather:${this.backgroundGatherTask.summary}`);