? changed to ?

For some reason whenever I set a custom permalink to have a ? in it the ? gets replaced by %3F. This is a recent error, as all my older blog postings have a ? in the link. But for some reason, going forward (even if I try and change the permalink on older postings) the ? is replaced. For example, a blog post that already exists:

http://blog.coachingwebsites.com/?i-really-could-use-a-nap
The permalink is:
?i-really-could-use-a-nap

That is also what is in the ‘custom_permalink’ Custom Field

But if make a new test blog and set the permalink to
?this-is-a-test
the ‘custom_permalink’ Custom Field will auto set itself to
%3Fthis-is-a-test

and the link for the blog post will be
http://blog.coachingwebsites.com/%3Fi-really-could-use-a-nap
While the following will just redirect to my blog homepage
http://blog.coachingwebsites.com/?i-really-could-use-a-nap

Again, only affecting new postings going forward, all previous postings work fine, as long as I don’t touch them or try and change the permalink. If I do it will start setting all ? to %3F and I can’t change it back.

http://ww.wp.xz.cn/extend/plugins/custom-permalinks/