Hi there,
The fix for this is to change a small part of the code you pasted in :)
Change this:
{% if line_item.tax_lines %}<td>
{% for tax_line in line_item.tax_lines %}
{{ tax_line.price | money }} {{ tax_line.title }}</td>
{% endfor %}
{% endif %}
To be this instead:
{% if show_line_item_taxes %}<td>
{% for tax_line in line_item.tax_lines %}
{{ tax_line.price | money }} {{ tax_line.title }}<br/>
{% endfor %}</td>
{% endif %}
Hope this helps!
Alternatively, you can check out my Order Printer Templates, which are customizable designs for Shopify's Order Printer, without needing to mess around with the code yourself ;)
Have a great week ahead!