diff --git a/emmet-core/emmet/core/tasks.py b/emmet-core/emmet/core/tasks.py
index f1286d4459..1879be6667 100644
--- a/emmet-core/emmet/core/tasks.py
+++ b/emmet-core/emmet/core/tasks.py
@@ -487,11 +487,11 @@ def last_updated_dict_ok(cls, v) -> datetime:
     def _validate_batch_id(cls, v) -> str:
         if v is not None:
             invalid_chars = set(
-                char for char in v if (not char.isalnum()) or (char not in {"-", "_"})
+                char for char in v if (not char.isalnum()) and (char not in {"-", "_"})
             )
             if len(invalid_chars) > 0:
                 raise ValueError(
-                    f"Invalid characters in batch_id:\n{' '.join(invalid_chars)}"
+                    f"Invalid characters in batch_id: {' '.join(invalid_chars)}"
                 )
         return v