I have had several times where the quilt sashes I am working on become wavy after I had finished sewing it. I stipple quilted the blocks in a quilt as you go and after finishing I find the binding has gone wavy as if I used the fabric on the bias( which I did not do) do you think I should stipple over it too so it won't look out of place. help please.

Probably so. The quilting process does cause some drawing and puckering of the fabric over the batting, and when the quilt is washed it will be even more pronounced. Might like to either Stitch In The Ditch to stabilize the seams, or as you say, do more quilting designs in the sashings themselves.
It will turn out lovely in the end either way.

I did sew in the ditch each side of the sashing and I think that made it worse. If I unpick it and stipple it will that help it sit better?

A rule of thumb (remember, there is no quilt police) is to be consistent in the density of your quilting. If you have heavy quilting in some spots, and light or no quilting in others, there will be unevenness in how the quilt lays.

I find If you do your SID first, you don't get the waving. I use sid as a stablizer. it workd great for me. Hope this helps with your next project. I think you will have to do some stippling to tame the sashing.

Thanks every one. It looks like I will be taking out the SID stitches before I start the stippling. Hopefully it will work. It always happen to me when I do a quilt to give away. This is to go the the local hospital for their raffle. Thanks :thumbup: to all of you.