[Plugin: Custom Post Type UI] Taxonomy item slug adding -2

I have been using Custom Post Type UI plugin for a while now with great success. I have 4 custom most types and several taxonomies for each. When adding a taxonomy item today I found that -2 was added to the end of the slug. This usually happens when the name is already listed however I only have 4 other items and this is not one of them. It is however listed under another taxonomy for another custom post type – but the other 4 items are also within this other taxonomy and not effected.

In other words I have:

http://www.example.com/taxonomy1/ItemA
http://www.example.com/taxonomy1/ItemB

http://www.example.com/taxonomy2/ItemA
http://www.example.com/taxonomy2/ItemB-2

How can I get rid of this -2 in the slug?

http://ww.wp.xz.cn/extend/plugins/custom-post-type-ui/