Ray fleck is normal, and it is often considered to be desirable, as it is a type of figure. This is one of the key attributes of quarter sawn oak. Medullary rays in oak generally appear in quarter sawn oak. However you may see them on edges of plain sawn oak. A pile of of plain sawn oak, will also usually have a quarter sawn board, or two mixed in as well.
I am not sure what you mean by flaking, as I have never encountered anything like that. A little tear out at times is unavoidable, and that is easily fixed with filler.
Also. White oak tends to have a coarse open grain, compared to most woods. I am wondering if you may be confusing this with checking, as the pores can be quite elongated, and large compared to other hardwoods. Standard practice is to apply a grain filler to achieve a flat surface prior to applying a film finish. Or you can leave it as is, especially when applying a finish with little to no build, such as "danish oil"
Actual surface checking (obvious cracks) is a major red flag, and it generally indicates poor drying. I have encountered this in maybe 1 or 2 pieces of white oak. I reject material with obvious cracks, and other indicators of serious drying stress.