In a freestyle project using a Git source, if you first build a job with a specific tag, then build with 'latest tag' (/tags/), it will be stuck with the specific tag you specified before.  

Recreation steps:

1) Repository URL (simple project with 1 small file): https://github.com/ediso74/Tagging.git

2) Refspec: +refs/tags/:refs/remotes/origin/tags/

3) Branch Specifier: */tags/v1.1

4.  Execute Windows build command (unix also):  more junk.txt

5. Build

When you click on build, you will see:

Revision: 352e66e7b09157983fc0a2c73339e99257be5fa6

• refs/remotes/origin/tags/v1.1

Console log:  ...

C:\Users\ediso\.jenkins\workspace\Tagging>more junk.txt
Going to Tag this file version with Tag v1.1

6.  Change Branch Specifier: */tags/*

7.  Build

nothing changes

Other notes:

1) If you create a new commit with a new tag, it will show the latest tag.