Meta Box clears saved field content

I found it, it was actually clearing when inputting apostrophe (‘) which conflicts in database save, to solve I used htmlentities() adn js replace to replace and save apostrophe with apostrophe code.

<input onkeyup="valid(this)" type="text" name="faq_2_title" style="width:100%;" placeholder="Tab Title" value="'. htmlentities($faq_2_title) . '"></input></h2>

js:

function valid(f) {
  f.value = f.value.replace(/'/g, '&#39');
}