Expresso Store2 - regular_price not showing in browsers other than Safari

Question

I'm having this problem with browsers not displaying the old price next to the sale_price except in safari. Both the index page where all products are listed and the singel productpage are not showing. Even in the pagesource is the old price not listed. Safari is showing in both pages without a problem.

This is the code I'm using:

<div class="price-holder">
  <div class="price">
    {if on_sale}
      <span>{price}</span>
      <del>{regular_price}</del>
    {if:else}
      <span>{price}</span>
    {/if}
  </div>
</div>

I've also tried this code:

<div class="price">
  {if on_sale}
    {price} <del>{regular_price}</del>
  {if:else}
    {price}
  {/if}
</div>

Both without success! Is there someone else who had encountered this problem? All help would be great.