Is it normal for a toddler to plateau in weight for a few months between 2-3 years old?

Yes: My expectation for feeding at that age is 3-5 good feeding days a month & the rest nibbling or grazing.Their interest also shifts to carbohydrates to sustain activity rather than protein to sustain growth. They may be stuck at a given weight or drop some, but most increase 3-4 lb/yr. As long as the growth rate & activity level are normal I don't worry about them.