diff --git a/CHANGELOG.md b/CHANGELOG.md
index dfedc482..374d0ef4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # CHANGELOG
 
+### 3.8.0
+- dev: log confusion matrices to Comet after each epoch.
+- fix: do not mix the two way to log IoUs to avoid known lightning [Common Pitfalls](https://lightning.ai/docs/torchmetrics/stable/pages/lightning.html#common-pitfalls).
+
 ### 3.7.1
 - fix: edge case when saving predictions under Classification channel, without saving entropy.
 
diff --git a/myria3d/callbacks/comet_callbacks.py b/myria3d/callbacks/comet_callbacks.py
index 84a82d0c..c9694376 100755
--- a/myria3d/callbacks/comet_callbacks.py
+++ b/myria3d/callbacks/comet_callbacks.py
@@ -33,7 +33,7 @@ def get_comet_logger(trainer: Trainer) -> Optional[CometLogger]:
                 return logger
 
     warnings.warn(
-        "You are using comet related callback, but CometLogger was not found for some reason...",
+        "You are using comet related functions, but trainer has no CometLogger among its loggers.",
         UserWarning,
     )
     return None
@@ -71,3 +71,16 @@ def setup(self, trainer, pl_module, stage):
             log_path = os.getcwd()
             log.info(f"----------------\n LOGS DIR is {log_path}\n ----------------")
             logger.experiment.log_parameter("experiment_logs_dirpath", log_path)
+
+
+def log_comet_cm(lightning_module, confmat, phase):
+    logger = get_comet_logger(trainer=lightning_module)
+    if logger:
+        labels = list(lightning_module.hparams.classification_dict.values())
+        logger.experiment.log_confusion_matrix(
+            matrix=confmat.cpu().numpy().tolist(),
+            labels=labels,
+            file_name=f"{phase}-confusion-matrix",
+            title="{phase} confusion matrix",
+            epoch=lightning_module.current_epoch,
+        )
diff --git a/myria3d/models/model.py b/myria3d/models/model.py
index 67c2752d..bf574623 100755
--- a/myria3d/models/model.py
+++ b/myria3d/models/model.py
@@ -4,6 +4,7 @@
 from torch_geometric.data import Batch
 from torch_geometric.nn import knn_interpolate
 from torchmetrics.classification import MulticlassJaccardIndex
+from myria3d.callbacks.comet_callbacks import log_comet_cm
 
 from myria3d.metrics.iou import iou
 from myria3d.models.modules.pyg_randla_net import PyGRandLANet
@@ -143,12 +144,14 @@ def training_step(self, batch: Batch, batch_idx: int) -> dict:
         with torch.no_grad():
             preds = torch.argmax(logits.detach(), dim=1)
             self.train_iou(preds, targets)
-        self.log("train/iou", self.train_iou, on_step=True, on_epoch=True, prog_bar=True)
+
         return {"loss": loss, "logits": logits, "targets": targets}
 
     def on_train_epoch_end(self) -> None:
-        self.train_iou.compute()
+        iou_epoch = self.train_iou.compute()
+        self.log("train/iou", iou_epoch, on_step=False, on_epoch=True, prog_bar=True)
         self.log_all_class_ious(self.train_iou.confmat, "train")
+        log_comet_cm(self, self.train_iou.confmat, "train")
         self.train_iou.reset()
 
     def validation_step(self, batch: Batch, batch_idx: int) -> dict:
@@ -173,7 +176,7 @@ def validation_step(self, batch: Batch, batch_idx: int) -> dict:
         preds = torch.argmax(logits.detach(), dim=1)
         self.val_iou = self.val_iou.to(preds.device)
         self.val_iou(preds, targets)
-        self.log("val/iou", self.val_iou, on_step=True, on_epoch=True, prog_bar=True)
+
         return {"loss": loss, "logits": logits, "targets": targets}
 
     def on_validation_epoch_end(self) -> None:
@@ -183,8 +186,10 @@ def on_validation_epoch_end(self) -> None:
             outputs : output of validation_step
 
         """
-        self.val_iou.compute()
+        iou_epoch = self.val_iou.compute()
+        self.log("val/iou", iou_epoch, on_step=False, on_epoch=True, prog_bar=True)
         self.log_all_class_ious(self.val_iou.confmat, "val")
+        log_comet_cm(self, self.val_iou.confmat, "val")
         self.val_iou.reset()
 
     def test_step(self, batch: Batch, batch_idx: int):
@@ -201,12 +206,11 @@ def test_step(self, batch: Batch, batch_idx: int):
         targets, logits = self.forward(batch)
         self.criterion = self.criterion.to(logits.device)
         loss = self.criterion(logits, targets)
-        self.log("test/loss", loss, on_step=True, on_epoch=True)
+        self.log("test/loss", loss, on_step=False, on_epoch=True)
 
         preds = torch.argmax(logits, dim=1)
         self.test_iou = self.test_iou.to(preds.device)
         self.test_iou(preds, targets)
-        self.log("test/iou", self.test_iou, on_step=False, on_epoch=True, prog_bar=True)
 
         return {"loss": loss, "logits": logits, "targets": targets}
 
@@ -217,8 +221,10 @@ def on_test_epoch_end(self) -> None:
             outputs : output of test
 
         """
-        self.test_iou.compute()
+        iou_epoch = self.test_iou.compute()
+        self.log("test/iou", iou_epoch, on_step=False, on_epoch=True, prog_bar=True)
         self.log_all_class_ious(self.test_iou.confmat, "test")
+        log_comet_cm(self, self.test_iou.confmat, "test")
         self.test_iou.reset()
 
     def predict_step(self, batch: Batch) -> dict:
diff --git a/package_metadata.yaml b/package_metadata.yaml
index e4938cd6..34cdfa22 100644
--- a/package_metadata.yaml
+++ b/package_metadata.yaml
@@ -1,4 +1,4 @@
-__version__: "3.7.1"
+__version__: "3.8.0"
 __name__: "myria3d"
 __url__: "https://github.com/IGNF/myria3d"
 __description__: "Deep Learning for the Semantic Segmentation of Aerial Lidar Point Clouds"