There are a bunch of calculations to optimize the file size. Just because the font fits in 4096x1024 doesn't mean it fits in 2048x2048. That would only work if the characters where square, but they are not. They are typically taller than wide, so generally the calculations would result in an even larger number in the height dimension.
A lot of these warnings have been around for years, so it may not be relevant. Hard to say.