diff --git a/pyproject.toml b/pyproject.toml
index 48926d3b..61e0afe0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,7 +16,7 @@ keywords = ["HSSM", "sequential sampling models", "bayesian", "bayes", "mcmc"]
 
 [tool.poetry.dependencies]
 python = ">=3.10,<3.12"
-pymc = "^5.14.0"
+pymc = ">=5.14.0,<5.15.0"
 arviz = "^0.18.0"
 onnx = "^1.16.0"
 ssm-simulators = "^0.7.2"
diff --git a/src/hssm/hssm.py b/src/hssm/hssm.py
index 5f23f572..e896bb8f 100644
--- a/src/hssm/hssm.py
+++ b/src/hssm/hssm.py
@@ -565,7 +565,11 @@ def sample(
         if self._inference_obj is None:
             self._inference_obj = idata
         elif isinstance(self._inference_obj, az.InferenceData):
-            self._inference_obj.extend(idata)
+            _logger.info(
+                "Inference data already exsits. \n"
+                "Data from this run will overwrite the idata file..."
+            )
+            self._inference_obj.extend(idata, join="right")
         else:
             raise ValueError(
                 "The model has an attached inference object under"
@@ -590,7 +594,11 @@ def sample(
                 # drop redundant 'rt,response_mean' variable,
                 # if parent already in posterior
                 del self._inference_obj.posterior["rt,response_mean"]
-        return self.traces
+
+        # returning copy of traces here to detach from the actual _inference_obj
+        # attached to the class. Otherise resampling will
+        # overwrite the 'returned' object leading to unexpected consequences
+        return deepcopy(self.traces)
 
     def sample_posterior_predictive(
         self,