Thanks Katherine.

These may be known issues related to the TTS engine 'word' callbacks:

In some cases, the TTS engine has "word" breaks at different times than the automation API. For example, when reading a number or date, the TTS engine may say more "words" than actually exist.

In the first one, we get "word" callbacks after "http", which throws off highlighting.

The second one may be related to reading dates or numbers. For example, "Sep 12, 2017" or "3/12/17", as well as 1,000,000 or $10.00, will have this problem. 

If you see this outside of dates or numbers, please let me know so I can have some examples!

More info:
b/69383330 (tts engine words in a date)
go/tts-behavior-examples

This happens with long numbers, money ($10.00), and places where TTS engine needs to give special word callbacks because the words are different from what's shown

 Issue 833033  has been merged into this issue.

Solution needs to be adding a end character index to the TTS callback utterance event.

This bug requires a change to TTS to be completely fixed.