I don't think I can trust TTS for language learning. I could be internalizing wrong pronunciation, and I wouldn't know. One time I tried Duolingo for Japanese already knowing a bit. To their credit I assumed it was recorded clips, until it read 'oyogu' as something like 'oyNHYAOgu', like it concatenated two syllable clips that don't go together. If I didn't already know, would I be trying to study and replicate that…
There are incorrect reading or Chinese readings occasionally, but you can tell when that happens due to the furigana being different