Hi,
We do that on purpose so that the text of the product name doesn't run over the other columns.
If you look in the invoice.php file you can see this line:
<?php echo implode('<br/>',$this->str_split_unicode(strip_tags($product->order_product_name),50));
which cuts the product name every 50 characters.
That's a conservative value we used because depending on the font used and the characters used, the width of 50 characters would be longer.
So in your case, you can just increase that value from 50 to 70 and it should display fine.