ok, this one doesn't work

src/transformers/models/ctrl/modeling_ctrl.py

@@ -612,6 +612,24 @@ def forward(
             attentions=transformer_outputs.attentions,
         )
 
+    def prepare_inputs_for_generation(self, input_ids, past_key_values=None, use_cache=None, **kwargs):
+        # Overwritten -- inputs_embeds not working properly
+
+        # only last tokens for inputs_ids if past is defined in kwargs
+        if past_key_values is not None:
+            past_length = past_key_values[0][0].shape[2]
+
+            # Some generation methods already pass only the last input ID
+            if input_ids.shape[1] > past_length:
+                remove_prefix_length = past_length
+            else:
+                # Default to old behavior: keep only final ID
+                remove_prefix_length = input_ids.shape[1] - 1
+
+            input_ids = input_ids[:, remove_prefix_length:]
+
+        return {"input_ids": input_ids, "past_key_values": past_key_values, "use_cache": use_cache}
+
     @staticmethod
     def _reorder_cache(
         past_key_values: Tuple[Tuple[torch.Tensor]], beam_idx: torch.Tensor