Found the link for this in the California update piece on TheProgressiveWing:

Citizens' Oversight Projects has filed suit in San Diego to stop certification of the count in that county until Registrar Vu provides answers to questions about how the audits have been completed and they are demanding preservation of discovery about the shredder truck photographed in front of the registrar's office after the election. If I understood correctly from the press conference, they also are asking that the ballots received by mail also be audited (apparently, they have not been). This is a CHALLENGE to the election, with five days left to prevent certification.

Here's the video: https://www.facebook.com/citizensoversight/

There are several earlier videos available here.

Registrar Vu has apparently been attempting to certify the election early, which is one reason the lawsuit was filed.

Citizens' Oversight Projects was founded in 2007 and began looking into election integrity issues.

Information about the lawsuit
This lawsuit tutorial video is from June 26:

This is the case they have with the count in the whole state:
Citizens' Oversight vs. Padilla

UPDATE: Looks like the previous lawsuit is not getting emergency response time as they requested - the judge is in the middle of a 5-week trial. They expect next steps to be in September.

The current case has been filed in San Diego county and will also be filed shortly in all the counties in Southern California (Counties: San Diego, Imperial, San Bernadino, Los Angeles, Riverside, Orange) which cover more than 50% of voters in the state, and eventually there will be a statewide suit. The suit claims misconduct in the election and they are contesting the certification. Michael Vu, of course, registrar in San Diego County has a record of election fraud in Ohio from 2004 where two of his underlings were convicted of wrongdoing and sentenced to 18 month jail terms.

At issue in the current suit(s) is the extensive disqualification of eligible voters. We've all heard the examples of training of poll workers to give Non Party Preference voters provisional ballots instead of the Democratic Crossover ballots necessary to select Bernie, the mysterious whited-out ballots where Bernie's name was removed seen by observers of the count, the disqualifying of students who are registered on campus but who do not have dorm room numbers over the summer between school terms whose ballots were apparently tossed for not having a room number affixed, issues with improperly disqualifying mail-in ballots, and of course the questions about the shredder truck which was parked in front of the voter registration office soon after the election about which the registrar's office has been mum. Observers were barred from observing directly during the counts. Questions to Michael Vu for explanation remain unanswered.

One of the most interesting pieces of information Lutz has is that in the tally of election day votes in San Diego, Bernie had 58% of the vote, while the early mail-in ballot totals were 58% for Hillary - he says a disparity of that size is atypical. What appears quite unclear is information about how the 1% audits were conducted because it sounds like there was ambiguity between whether these audits were done by precinct or by batches - Vu's office refuses to clarify, apparently. It also seems that the areas which were spot-checked for the 1% audit were identified ahead of time (which takes away any assurance of consistency a random count offers).

I am left feeling that the election has been anything but transparent.

Acknowledged in this video is that Riverside County has acknowledged tampering with voter registration.