diff --git a/rowers/dataprep.py b/rowers/dataprep.py
index bfd68570..63a40939 100644
--- a/rowers/dataprep.py
+++ b/rowers/dataprep.py
@@ -766,8 +766,12 @@ def fetchcp_new(rower, workouts):
     if len(data) > 1:
         df = pl.concat(data)
 
+
     try:
-        df = df.group_by(pl.col("delta")).agg(pl.max("cp"), pl.max("workout"), pl.max("url")).sort("delta")
+        #df = df.group_by(pl.col("delta")).agg(pl.max("cp"), pl.max("workout"), pl.max("url")).sort("delta")
+        df = df.groupby('delta').agg([
+            pl.all().sort_by('cp').last(),
+        ])
     except (KeyError, ColumnNotFoundError):  # pragma: no cover
         return pl.Series(dtype=pl.Float64), pl.Series(dtype=pl.Float64), 0, pl.Series(dtype=pl.Float64), pl.Series(dtype=pl.Float64)
 
diff --git a/rowers/tests/testdata/testdata.tcx.gz b/rowers/tests/testdata/testdata.tcx.gz
index f4be04e3..9b3705d1 100644
Binary files a/rowers/tests/testdata/testdata.tcx.gz and b/rowers/tests/testdata/testdata.tcx.gz differ
diff --git a/rowers/utils.py b/rowers/utils.py
index 9e7d5054..ee7ca475 100644
--- a/rowers/utils.py
+++ b/rowers/utils.py
@@ -361,9 +361,12 @@ def isbreakthrough(delta, cpvalues, p0, p1, p2, p3, ratio):
 
     pwr *= ratio
 
-    delta = delta.cast(pl.Int32)
-    cpvalues = cpvalues.cast(pl.Int32)
-    pwr = pwr.cast(pl.Int32)
+    try:
+        delta = delta.cast(pl.Int32)
+        cpvalues = cpvalues.cast(pl.Int32)
+        pwr = pwr.cast(pl.Int32)
+    except:
+        return False, pl.DataFrame(), False
 
     btdf = pl.DataFrame({
         'delta': delta,