If it is 2 types of materials laminated, they might expand and contract at different rates, creating more stress on joints, and possibly warping as one side expands more than the other.
Laminates of the same material would expand/contract at a different rate than the glue material. Then if they are cross grained, then each sheet would expand more in a different direction.
Just thinking out loud, but it seems to me a solid material would be safer.
It gets into the high 80's in my upstairs, and I haven't had any problems from that. My 6 string is about 25 years old and is only showing some expected bowing in the face from being so old and not expensive to begin with.
With the temp changes from day to night, all my guitars go off "A440" depending on the time of the day, but they don't seem to suffer otherwise.
...so ever since then, I always hang on to the buckle.
