Is it standard behaviour for cd to automatically choose when given an incomplete directory name?

I have three folders called ProjectA, ProjectB and ProjectC. When I tab-complete cd to cd Project and press Enter, it chooses ProjectC. I've found this is also the case with other similar cases; it defaults to the last in lexicographic order (but this may also be most recently changed/added). Is this expected default behaviour for cd, or have I set something by accident here? I'm running OSX 10.10.3, with bash 4.3.