Thank you for reporting this issue. You are right, this should be a diode symbol. We will have this fixed for you and we'll get back to you soon.
Thank you for patiently waiting. We have updated this part for you and you can now download it here: https://www.snapeda.com/parts/SESD0402X1UN-0020-090/Littelfuse%20Inc./view-part/?ref=search&t=SESD0402X1UN-0020-090. Kindly let us know if you have questions about this.