The automated polynomial fit in wavelength has generated a wavelength range which is inconsistent with the expected scope of wavelengths (either as specified by the user, or as calculated from previously identified orders).
The user should investigate the identification of this order manually to verify the situation. In most such cases allowing a larger search scope for the order and/or manually rejecting the incorrect identification using the AI option in ech_idwave will lead to a more favorable identification.
Martin Clayton