I have a similar problem with ITALIAN language and Discount codes. In JS there is an italian translated text with apostrophe closing the string unexpectedly. This is the line in JS from console:
jQuery(‘#pmpro_level_cost’).html(‘<p>Il codice TEST è stato applicato all’ordine.</p><p>The price for membership is 2€ per Mese. </p>’);
as you can see where it says “all’ordine” should be escaped, or at least avoid apostrophes in translations.
In the meantime I resolved manually editing the translation with “Loco Translate” plugin