SourceTree keeps creating truckloads of git processes in the background

About every few seconds, SourceTree creates a spree of git processes in the background usually in 4 or more subtrees.

This might be related to https://answers.atlassian.com/questions/135507/sourcetree-painfully-slow

I've disabled:

• "Automatically refresh" in the git repository
• "Refresh remote status in the background" in the git repository
• "Refresh automatically when files change" in the global options
• "Check remotes for updates" in the global options

I'm at SourceTree 1.9.6.1 on Windows 7 x64.

The processes make the 4 core system use ~60% of CPU on average slowing down my work.

Example screenshot:

https://www.dropbox.com/s/hm9xg1yjbr2yvlb/Screenshot%202016-11-17%2013.10.51.png?dl=0

--jeroen