Oil enum not allowing seperator characters

[InsiteFX]

Why will it not accept an underscore or a space then? I can enter them in the field name using git bash.

Oil generate line 683:
preg_match('/([a-z0-9_-]+)(?:[([0-9a-z,\s]+)])?/i', $part, $part_matches);

RegExp: /([a-z0-9_-]+)(?:[([0-9a-z,\s]+)])?/i
pattern: ([a-z0-9_-]+)(?:[([0-9a-z,\s]+)])?
flags: i
2 capturing groups:
group 1: ([a-z0-9_-]+) <-- field name
group 2: ([0-9a-z,\s]+) <-- field value - this is not allowing for the underscore.

This is FuelPHP 1.7 dev