If the marker is in the middle of the United States it is most likely where Google thinks the center of the map should be and is returning the “Home marker”.
Check:
1) What is the setting under MAP/Center Map ? First box under AT STARTUP:
aif you have not designated a center map at or it is showing United States , i Google assumes the middle of the Untied states , usually in Kansas.
To change this Set ting: Ttpe in the box a location ,or a state, or a city, . I would select somewhere in the area where your locations are in Southern California.
2) Otherwise if you want the center map in Kansas: Reset the Home map marker: You can select the Blank marker (usually the second one in under the map marker icons or delete the home marker url altogether. Depending on any add-ons they have there are also additional shortcodes
See documentation for Map panel settings
How radius works and other information.