Why does sourcetree change my autocrlf to false?

[Niels Ole Holck]

On my work we want to use autocrlf=input

In git bash, if I type:
git config --global core.autocrlf
it prints:
input

If I open "Tools->Options" in SourceTree (version 3.4.20) I can see that there is a checkbox under the Git page for "Configure automatic line endings handling by default (recommended)".
It is unchecked. When I close the Options window (either X or OK), the global setting for autocrlf is changed to false.
This is not intuitive. Is there any way to prevent this?

Thanks :)