My bad: the marriage of Konstanze of Hohenlohe-Langenburg and Prince Franz Joseph of Hohenlohe-Schillingsfürst ended up following the rule that all the children be brought up in the religion of their father -- not a mixed arrangement. In any case, the couple became the parents of only sons.

So the situation was no different from that of the marriage of her sister Agnes to another Catholic prince (Konstantine, Hereditary Prince of Löwenstein-Wertheim-Rosenberg). It had nothing to do with the fact that the children born to that union were orphaned early: Adelheid and her brother would have been brought up in the religion of their father, even if their Lutheran mother had lived.