Waze does have an affinity for street names, and it may be avoiding the transition to Isabel.
Livemap shows this as well: http://www.waze.com/livemap/?zoom=14&lo ... g=62935506
I wonder if the parking lot road here or one of the junctions might be corrupted? That's about the point on livemap where the routing switches to using Isabel. It's just a parking lot road, so I'd advise trying deleting the parking lot, delete the junctions on Vineyard, then redraw the parking lot as at least two segments instead of one.
Test in livemap again on Sunday.
EDIT/OT: Ahhhh, Livermore. "New" exit 51 was the first interchange I staged before it was opened and had it available for routing just a few days after it opened, before Google.