diff --git a/beats/backbone.py b/beats/backbone.py
index 43a7207dc..5d5a1bfc4 100644
--- a/beats/backbone.py
+++ b/beats/backbone.py
@@ -113,7 +113,7 @@ def extract_features(self, x, padding_mask=None, tgt_layer=None):
 
         x_conv = self.pos_conv(x.transpose(1, 2))
         x_conv = x_conv.transpose(1, 2)
-        x += x_conv
+        x = x.clone() + x_conv
 
         if not self.layer_norm_first:
             x = self.layer_norm(x)