Is this an acceptable set of back plates?

[MountainMetal]

Received this set of Purple Heart from a supplier. One side is cupped bad and kinda seems to not be booked matched. I could probably deal with it but the tap tones of each side are so different that I believe they are not even from the same log. I am new to instrument building and is this normal.

[tippie53]

contact them
They appear to be warped most likely still wet. You can dry them and they may return to flat but allow the supplier a chance to make this right for you

[MountainMetal]

Moisture must be under 5%. Won't register on my moisture meter. Other half is at 5.3%. I will let it set in my shop for awhile. My humidity is maintained between 45% and 50%. I have another set of purple heart from same supplier and it is perfect. We will see.
Thank you!

[phavriluk]

I've joined and used backs less flat than these without any problem - - - - but I am nobody's idea of any kind of expert. Bracing a domed back has had a positive effect for me.

About the bookmatching, for me it's hard to tell from that picture. . I'd try to match up the end grain on the two panels and see how (if) they can be made to line up. If they can't be lined up, then I think there's a good suggestion that the panels aren't bookmatched. I wouldn't take the vendor's pencil lines as gospel for alignment.

[tippie53]

I also have used propellered backs once thinned and braced that will hold but
this appears to be one of 2 things , either a slice from a twisted tree or one that isn't
totally dried