I have used a lot of flannel over the years (I have made about 100 receiving blankets, more than 100 burp cloths and flannel quilts). I always wash the flannel -- it does not matter the brand , I have had them all shrink various amounts. A couple of years ago, was sewing with LQS flannels only (they were on sale) and one shrank 4" in length.
I just got done making another set of receiving blankets -- I had bought some at Joanns and could only use about half of it after I washed it. Even though if felt good when I bought it, when it was washed it became very limp. So disappointing. Fortunately I had some left over from a previous project and was able to make what I needed.
I hope I don't need to work with it any more since the the quality is not as good as it was and the price of the LqS fabric is getting to be too much.