Outdated version 11.0 of W3 Total Cache has a bug which prevents the proper execution of radio button choices where not only labels are used but values, too (Checkbox ‘show values’ checked). If a value is set to 0 (zero) the resulting <input> in the frontend will look like <input name="input_45" type="radio" value id="choice_14_45_0"> The attribute value is missing an assignment which should be value=“0”.
Solution: Update to W3TC v0.12.0 and clear the minify cache as well as all other caches!