Could Robin have had a big behind the scenes retcon?

I just had a thought about Robin's skin changing after the time skip. I think Oda may have had some kind of idea about the lore of her genealogy and, at some point, changed it since he hadn't pulled the trigger on it yet. If any of you agree, I'd like to hear your thoughts on what Oda could have planned for her before he changed her appearance in the time skip. Sorry if this sounds stupid I'm new to the series?

Edit: I did not know this was a simple case of an animation mistake, please forgive the misunderstanding, I just wanted to talk about cool lore stuff and I did not wish to offend so so so many people so fast.