diff --git a/src/scida/customs/arepo/dataset.py b/src/scida/customs/arepo/dataset.py
index 7ba4beb2..77946e9e 100644
--- a/src/scida/customs/arepo/dataset.py
+++ b/src/scida/customs/arepo/dataset.py
@@ -52,6 +52,10 @@ def prepare(self, *args, **kwargs) -> None:
                 pnum = int(splt[1])
                 offset = offsets[pnum]
                 length = lengths[pnum]
+                if hasattr(offset, "magnitude"):  # hack for issue 59
+                    offset = offset.magnitude
+                if hasattr(length, "magnitude"):
+                    length = length.magnitude
                 for k, v in self.data_backup[p].items():
                     self.data[p][k] = v[offset : offset + length]
         snap.data = self.data
diff --git a/tests/test_issues.py b/tests/test_issues.py
new file mode 100644
index 00000000..fa7f186d
--- /dev/null
+++ b/tests/test_issues.py
@@ -0,0 +1,14 @@
+# tests for gh issues. to be cleaned up and moved to the right place eventually
+from scida import load
+from tests.testdata_properties import require_testdata_path
+
+
+@require_testdata_path("interface", only=["TNG50-4_snapshot"])
+def test_issue_59(testdatapath):
+    # current testing of interface did not include units=True yet.
+    obj = load(testdatapath, units=False)
+    _ = obj.return_data(haloID=42)
+    # for units=True, this would be a pint.Quantity, so we need to check for that
+    # in the Selector
+    obj = load(testdatapath, units=True)
+    _ = obj.return_data(haloID=42)