This is untrue. We may have plateaued but we haven't yet seen a significant drop from the peak yet. 4 days ago there were 115 deaths, then 93 the next day, then 89 the next, that's as high as the peak you're referring to. Source - daily department of health releases https://www.cdph.ca.gov/Programs/OPA/Pages/New-Release-2020....
The drop you are inferring from your graph appears to be a be a reflection of a noisy data set, and the graph is a week out of date.