Local lightnong not on map, even though there are detectors

[GeezerD]

Another instance of unmapped or undetected lightning in the SF Bay Area, within the last 15 minutes, in Alviso.
We heard it, and got an notification from the android app, Lightning Pro (paid version).
Closest Blitzortung detection is about 40 miles south, around San Luis Reservoir.

Any ideas why? Lack of local receivers that contribute to the network? Will that do it?
thanks for reading
Geezer D

And again, just now, in Milpitas, same android service, with my own audio confirmation!
Nearest strikes shown in Blitzortung are still about 40 miles south of here.