Logical error when running example_nl_perturbed.py

I get:

Dynamics Matrix([[-x1], [d1 - e2 + x1**2*x2 + x2**3 - x2 - (e1 + x1)**2*(e2 + x2) - (e2 + x2)**3], [x1], [-d1 + e2 - x1**2*x2 - x2**3 + x2 + (e1 + x1)**2*(e2 + x2) + (e2 + x2)**3]]) are not yet homogeneous.
Make Homogeneous with degree 2 (Default: 2)

However, the default degree should not be 2. It should be equal to the highest degree among all terms of the dynamics. Here, the highest degree is 3, so the default should be 3 as well.