thrownullpointer

Can you provide a git log of the commit performed by this user?

This is completely empty?

The jenkins job config xml isn't actually updated until you trigger your next job. I think your job was just out of synch...

What do your jenkins jobs configurations look like? I have the same setup (we actually have 1 job per branch). If someone modifies master (by a commit) it doesn't trigger...

Modify web.xml to allow unauthorized access to http://jenkins.url:8080/git/

I think it's fine you need to provide all parameters when updating the hook.

Can you print the results of git log that has the commit performed by this user?

You need to configure the quote period on your job See https://jenkins.io/blog/2010/08/11/quiet-period-feature/

Can you provide the XML config of one of your jobs that is being triggered, but shouldn't be?

This appears to still point to a bad url.