BUG: Fix wrong SparseBlock initialization in quantile method

Author: Licht-T

pandas/core/internals.py

@@ -1581,6 +1581,10 @@ def _nanpercentile(values, q, axis, **kw):
         result = self._try_coerce_result(result)
         if is_scalar(result):
             return ax, self.make_block_scalar(result)
+
+        if isinstance(self, SparseBlock):
+            result = SparseArray(result.flatten())
+
         return ax, make_block(result,
                               placement=np.arange(len(result)),
                               ndim=ndim)