Steps to reproduce:

1. open firefox
2. open for example the news article https://www.vrt.be/vrtnws/nl/2018/02/17/russische-vuile-trucs--wakkere-zwarten--verenigde-moslims-van-am/ (sorry, this is in dutch, it is the website of the Flemish broadcaster)
3. press 1 twice to get to the heading with the title
4. press nvda+a to speak out all content from that point.

perceived behavior:
text is spoken out as supposed, except that here and there it appears as if the cursor (probably not the right term in say all) jumps back a few words, or a word, or even half a word.
I'd say this happens with all articals on this website, although my impression is that it is mainly with longer articles.
I have perceived this behavior only on two or three other websites: thus it is not a very common issue.
It is also my impression that this jumping back behavior is pretty random (thus it is not always at the same position in the text that it happens).

sysstem config:

• OS: windows 10 (happens also on win 8.1)
• NVDA:
  • installed version, version 2017.4
  • voice settings: English (GB), max,rate 80, rate boost not checked
  • synth: espeak
• firefox: 58.0.2 (64-bit) (but problem was for sure already present in v57 and perhaps before)

what is simplest way to record the speech output? Having it in a file will probably more illustrative than a couple of words trying to describe the behavior.

Given the jumping back behavior, is it possible this is a timing/syncchronization problem?