Oh My God. Took me literally 6 weeks to figure this out. My kids grew up. Pets came and went. Seasons changed. Much of my life was lost. Please Apple. You can do better. Please I beg of you.

This is a frustrating bug that has been around in various incarnations since iOS 15. I hold no hope that Apple will ever fix. Have resorted to 3rd part TTS services as not able to rely on this for mission critical application features. Sadly they cost money, but I don't see any real alternative. On the plus side, the voices are about a million time better than the broken/garbage ones that are supposedly part of the AVFoundation framework. Godspeed.