diff --git a/areal/infra/workflow_executor.py b/areal/infra/workflow_executor.py
index 949d2af0b..00a3decc3 100644
--- a/areal/infra/workflow_executor.py
+++ b/areal/infra/workflow_executor.py
@@ -869,14 +869,18 @@ async def _dump_trajectory(
             self.logger.warning(
                 "Trajectory missing 'versions' field, defaulting to current inference engine version."
             )
-            versions = [self.inference_engine.get_version()]
+            all_versions = None
+            default_version = self.inference_engine.get_version()
         else:
-            versions = traj["versions"].flatten().tolist()
+            all_versions = traj["versions"]
 
-        tail_version = max(versions)
-        head_version = min(versions)
+        global_tail = (
+            all_versions.max().item()
+            if all_versions is not None
+            else default_version
+        )
         # Create versioned directory
-        version_dir = os.path.join(dump_dir, str(tail_version))
+        version_dir = os.path.join(dump_dir, str(global_tail))
         await aiofiles.os.makedirs(version_dir, exist_ok=True)
 
         # Handle batched trajectories
@@ -894,6 +898,25 @@ async def _dump_trajectory(
                 if mask[-1] != 1:
                     continue
 
+                if all_versions is not None:
+                    sample_versions = all_versions[i, :seqlen].tolist()
+                    output_versions = [
+                        v for v, m in zip(sample_versions, mask) if m == 1
+                    ]
+                else:
+                    output_versions = [default_version]
+
+                head_version = min(output_versions) if output_versions else -1
+                tail_version = max(output_versions) if output_versions else -1
+
+                # RLE: [[version, count], ...]
+                version_rle = []
+                for v in output_versions:
+                    if version_rle and version_rle[-1][0] == v:
+                        version_rle[-1][1] += 1
+                    else:
+                        version_rle.append([v, 1])
+
                 prompt_end = seqlen - sum(mask)
                 prompt_ids = ids[:prompt_end]
                 completion_ids = ids[prompt_end:]
@@ -913,6 +936,7 @@ async def _dump_trajectory(
                     "prompt_len": prompt_end,
                     "head_version": head_version,
                     "tail_version": tail_version,
+                    "version_rle": version_rle,
                     "reward": reward,
                     "prompt": prompt_text,
                     "completion": completion_text,