multiple choice options' value validation inconsistency

1. Create a new custom filed of type Alphanumeric/Select.
2. Insert a multiple choice option with label 'label' and value 'val-ue'.
3. Save. [The filed saves properly.]
4. Edit Multiple Choice Options.
5. Edit option 'label', try to save it.

Result: option can't be saved, because the value contains a dash.

Expected result: the rules for accepting multiple options' values should be the same upon creation and edition.