My payment dates (entered in the worksheet) are 4/5/21, 6/9/21, 9/9/21, and 1/10/22. As I wrote above, they were all timely.
[According to TurboTax support, this is a known bug...] -- Not exactly... I think that the only TurboTax problem is the "Payment Due Dates" in Form 5805 Worksheet II Part I - the first column heading should be April 15, 2021 rather than July 15. (The first payment was delayed in 2020, and perhaps that one-time change hasn't been reverted.)
The problem is in the opening line in my original post: "I made four timely equal estimated tax payments for 2021." I am embarrassed to say that today I learned that California's estimated tax payment schedule is 30% in April, 40% in June, no requirement in September, and 30% in January. Equal payments can result in a penalty. Thanks for your patience.
