diff --git a/packages/python/plotly/_plotly_utils/basevalidators.py b/packages/python/plotly/_plotly_utils/basevalidators.py
index 2b799c474cb..e0c93699e72 100644
--- a/packages/python/plotly/_plotly_utils/basevalidators.py
+++ b/packages/python/plotly/_plotly_utils/basevalidators.py
@@ -7,7 +7,6 @@
 from importlib import import_module
 import copy
 import io
-from copy import deepcopy
 import re
 import sys
 
@@ -2662,24 +2661,20 @@ def validate_coerce(self, v, skip_invalid=False, _validate=True):
             for v_el in v:
 
                 if isinstance(v_el, BaseTraceType):
-                    # Clone input traces
-                    v_el = v_el.to_plotly_json()
+                    if isinstance(v_el, Histogram2dcontour):
+                        v_el = dict(type="histogram2dcontour", **v_el._props)
+                    else:
+                        v_el = v_el._props
 
                 if isinstance(v_el, dict):
-                    v_copy = deepcopy(v_el)
-
-                    if "type" in v_copy:
-                        trace_type = v_copy.pop("type")
-                    elif isinstance(v_el, Histogram2dcontour):
-                        trace_type = "histogram2dcontour"
-                    else:
-                        trace_type = "scatter"
+                    type_in_v_el = "type" in v_el
+                    trace_type = v_el.pop("type", "scatter")
 
                     if trace_type not in self.class_strs_map:
                         if skip_invalid:
                             # Treat as scatter trace
                             trace = self.get_trace_class("scatter")(
-                                skip_invalid=skip_invalid, _validate=_validate, **v_copy
+                                skip_invalid=skip_invalid, _validate=_validate, **v_el
                             )
                             res.append(trace)
                         else:
@@ -2687,9 +2682,13 @@ def validate_coerce(self, v, skip_invalid=False, _validate=True):
                             invalid_els.append(v_el)
                     else:
                         trace = self.get_trace_class(trace_type)(
-                            skip_invalid=skip_invalid, _validate=_validate, **v_copy
+                            skip_invalid=skip_invalid, _validate=_validate, **v_el
                         )
                         res.append(trace)
+
+                    if type_in_v_el:
+                        # Restore type in v_el
+                        v_el["type"] = trace_type
                 else:
                     if skip_invalid:
                         # Add empty scatter trace