Only happens off certain combos, and only if you do a MK jumping slash linker right before the Eclipse ender. Happens pretty consistently in a variety of openers if you open with a shadow move and keep the combo short with lights. Not sure if it's possibly off anything other than shadow openers.
The combo here is: bf+PP, lp auto, bf+mk, lp auto, bf+mk, du+P
TL;DR for Sabrewulf mains: Do not do jumping slash into eclipse to end your combos.