I have a setup where a VSTS build starts a jenkins job. I use that build for building pull requests. I configured the refspec according to the instructions. 

Everything worked fine, but recently the tfs plugin builds the wrong PR. In the logs I see this message

skipping resolution of commit <commit id>, since it originates from another repository

After that statement, it falls back to a previous VSTS PR branch and builds the wrong commit.

 UPDATE

I found out that it works if I enter the git url in the jenkins build with only lowercase characters. As soon as I use uppercase characters in the git url, it thinks that it's a different repository. I don't know if the actual issue is in this plugin or in the git plugin.