Just more information on this.

With AB150, as of today (2.6.2022) the credit is severely limited by California Tentative Minimum Tax.  Because of this, many business did not want to make a full payment by 12.31.2021 and get partial credit on their CA tax return.   

California current has a fix in process for this (AB87) and their budget (see Economic Growth tab etc https://www.ebudget.ca.gov/budget/2022-23/#/BudgetSummary ).

This leave cash basis pass trough's in a bind:  there is still risk of TMT limitation, so those that held off on deciding on payment now may not be able to deduct in 2021 if they are cash basis.   

I'm not sure if we will get any IRS clarity on this, but the "safe" answer is the deduction is in the year paid for cash baiss tax payers.... and the "hopeful" answer is there will be some update allowing us to accrue this deduction for 2021 since California's system has been a mess.  cheers!