Nothing will come of this, unfortunately.
But the bigger picture - if Schiff claimed, in writing, that his PRIMARY residence was in Maryland... then he was absolutely ineligible to run for office in California (and California has no authority to override that). One could push election fraud as well.
But again - absolutely NOTHING will come of this.
The residency issue is a bit complex.
All members of Congress have one residence in their home state and one in the metro DC area.
That is good enough for them to be members of Congress. It does not matter for that purpose which is their claimed primary residence.
The primary residence issue kicks in for tax purposes (federal and state), mortgage purposes (subject of this thread) and probably other issues as well.