This sounds like the new neural AI from google or openai. However It's hard to place - where did you find the reference?

Microsoft voices are good but I can't hear this one: https://azure.microsoft.com/en-us/products/cognitive-services/text-to-speech/#features

Potentially it could be one of these https://mycroft.ai/mimic-3/

The mimic AI voices sound great and are also offline: https://github.com/MycroftAI/mimic3-voices There are a lot of voices to choose from - some are more human than others https://mycroftai.github.io/mimic3-voices/

I understand it's not your specific but the female English (US) vctk_low -> p225 is phenomenal.