diff --git a/src/parcels/_chunk_cached_array/core.py b/src/parcels/_chunk_cached_array/core.py
index bded6d1a5..bf73682a3 100644
--- a/src/parcels/_chunk_cached_array/core.py
+++ b/src/parcels/_chunk_cached_array/core.py
@@ -140,6 +140,11 @@ def _raw_vindex(self, *indices: np.ndarray) -> np.ndarray:
 
     def _vindex_get(self, indexer: VectorizedIndexer):
         key = indexer.tuple
+        # The chunk-cache fast path requires a fancy integer array per dimension.
+        # Some dims (e.g. unindexed extra dims) may come through as a bare slice
+        # instead, so fall back to dask's own vectorized indexing in that case.
+        if any(isinstance(k, slice) for k in key):
+            return self.array.vindex[key].compute()
         return self._raw_vindex(*key)
 
     def _oindex_get(self, indexer: OuterIndexer):