It Might Be Vid

I've been making a lot of eggs for a friend who's been doing an egglocke in scarlet and violet, and when I add the eggs to a box so I can send all the eggs together, the eggs will sometimes lose the nickname when I press "Set" to put them in the box. I've tried toggling the nickname box off and on, I've tried restarting pkhex, but it seems to be random.