Question HTTP 200 and 301 headers

I have a sitemap.xml file on both on my local dev machine and my production system.  I thought I had done a pretty good job with construction these files but recent testing showed them to be an absolute mess (
Anyway, I have two url's for testing.  I am looking at the headers for each queries below.
query 1:    skatekey.net/tree/peters/individual/I0001/Johannes-Peters
query 2:    skatekey.net/tree/peters/individual/I0001
Both queries work.  But, query one returns a HTTP 200 header and query 2 returns an HTTP 301 header.
The test site uses pretty URLs.  I have removed every significant thing from the .htaccess file.  
My question is, why a 301 header?
 

I don't think something is wrong here.

A full url to a person consists of:
/tree/{tree}/individual/{xref}/{slug-name}
Your second example misses the slug-name part, so you get redirected. That's the 301 status code.
And your sitemap contains only full correct urls.

If the slug is missing or just *different* to the expected slug, then you will get a redirect only the current page.