Siri (French) mispronouncing "St-" names

Siri has been mispronouncing French "St-" names for years (I bug reported this as #22774930 over two years ago):

Phone language (and Siri language) set to French (Canada) and issue is also present if I use one of the French (France) voices. Any contact with the last name starting with "St-" (short for Saint) is pronounced wrong.

For example, St-Pierre will be pronounced ɛstepjɛr (estépierre) instead of sɛ̃pjɛr (saint-pierre) (French IPA). Teaching Siri to pronounce it properly, either via Siri itself or using the contact's phonetic name field yields no result as it seems to get ignored. A workaround is to change the name to "Saint-Pierre" but this should not be required.