SourceTree doesn't list local branches with underscore '_' as Tracked

When listing Tracked Branches for a Push to Origin, SourceTree doesn't list branches that contains the underscore character '_'.

Example,

for a branch say with a name 'Feature_Changes' this branch will not be listed under 'Branches to Push' in the Push to Origin pop-up dialog.

if the branch were to be renamed to 'Feature-Changes' this branch will now show under 'Branches to Push' in the Push Origin pop-up dialog.