No, you simply have to delete the woocommerce_de_small_business_regulation_text and output it in another way/location. IIRC this function is used to echo something upon calling the woocommerce_get_order_item_totals
filter.
There’s an important difference between actions and filters in WordPress:
Actions are meant to execute a function or output certain text/html, filters are meant to change/filter a variable.
In this case, this is about a filter for the woocommerce totals: woocommerce_get_order_item_totals
is meant to make changes to the total rows (add new rows, modify how it’s displayed, labels, etc.). This filter gets executed when the total rows are requested. Because it’s not an action, no output is expected/supposed to be given. I can only request these totals in the middle of the table, because I have to loop through each <tr>. Your filter (mistreated like an action) gives this kind of output:
<table>
Umsatzsteuerbefreit nach §4 UstG
<tr>
<td>Label</td>
<td>€10</td>
</tr>
</table>
As you can see, this is not proper HTML (there’s not supposed to be any output outside of a td), and that’s why the PDF engine crashes.
I advise you to contact German Market Press support to come up with a better solution.
Hope that helps!
Ewout