VoiceOver-voices behave oddly - Enhanced quality turned low quality and won't turn back
This morning VoiceOver suddenly started behaving oddly on my phone. I use 3 different languages on my phone: English (standard), Swedish and Dutch (Router languages). When switching from English to Dutch to read a message, I suddenly discovered that the Dutch voice had turned from enhanced quality to low quality, how is a mystery. Baffled, I switched back to English, only to discover that that one had turned down to low quality as well. Weirdly enough, the Swedish voice is still on enhanced, both voicewise and visibly in the settings.
I went into settings to check things. All voices are set on Enhanced quality. I have restarted VoiceOver (several times), restarted the phone (both normal restart and the one with lock- and home-button simulatniously), have tried switching the voices from normal to enhanced, have deleted and reinstalled the Dutch router language - no result. The English standard voice and the Dutch router stays low Q and the Swedish high, no matter what I do.
This really happened out of the blue - one moment things were normal, the next weird. Does anybody know what might have happened? Is there a fix? Or is the only way to factory reset the phone and start from scratch again? ...which would probably mean I'd have to update to iOS13. Ugh.
I'm using an iPhone SE, currently on iOS12.4.1. Super grateful for any ideas on how to fix this.