Contorted filbert, bronzing leaves?

Hello!

I got a contorted filbert this spring to add to our garden, and it's currently in a large pot until we find a place for it. I went out to check on it and I noticed that some of the leaves are starting to bronze. I thought maybe it was getting too much sun, but my research has found that they prefer full sun. I couldn't find anything on this with an initial search, and am curious if anyone else knows about this?

Thoughts?