This happens to me a lot, sometimes with how hair falls and such.
Sometimes I even go "oh okay yeah I remember now" months pass and I find an old drawing and realize how off I was but this new style just looks better now. And then it's just minute details like say.....a hat. A whole hat.
I think one that legitimately scared me was that I forgot how long a character's arms were, and I kept trying and nothing was looking right. I was so frustrated like...how do you just forget to draw one character's arms and everyone else looks okay. |"D