"EDIT: Verified, as would be expected, there is no "turn" instruction given for any left or right turn at this intersection."
Perhaps there is something different about the ones you 'reviewed' since you don't provide which lanes you tested or which directions you were traveling from/to. You certainly did not test them all.
For this intersection specifically, if you are coming from North Village Road northbound on Wiehle to turn right onto north bound Reston Parkway, you are wrong.
You get a 'keep right' to move into the turn lane
This is followed by a 'Turn right at Reston Pkwy'.
That's right off the Waze Navigation List. I don't get the 1/10 mile alert on this because I set it up from my house which brings me onto Wiehle at North Village Road, only 334 feet from the 'keep left'.
And this is true for the entire test area I set up down Wiehle from Reston Avenue to Baron Cameron. And if you are coming from far enough away, you get an advance alert at 1/10 mile before the keep right.
Perhaps on the pathway that you tested there is something different about the way the roads are designated.
So, I tested coming along this same route, but turning left at Reston Parkway. Interestingly, the Waze navigation list gives the keep left, but you don't get the left turn instruction - just as you report.
Looking at these 2 turns I see nothing different in the way different designations that they have for any entry. But Waze returns different results for them.
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Area Manager: Northern Virginia; Wardensville, WV - Strasburg, VA; Capon Bridge, WV - Winchester, VA