Completely meaningless. Could be a dither effect in the algorithm reading how much fuel is left. My HEV range remaining is always off by more than one hundred miles when I fill my tank. It only approaches the real fuel remaining in the last hundred miles. What is 2 miles in a range that exceeds 600 miles (700 for me in the summer)? Meaningless.
As lafe005 was trying to say, it could also be that you had climate control on for heat and the engine turned on unbeknownst to you (can be easy to miss). And as I understand it, even the PHEV in EV mode will once in a while run the engine, perhaps for diagnostics, or simply to lubricate everything.
2018 Kia LX HEV Metal Stream with Advanced Tech