I know I had troubles with a 592B in 2016 and 2017 on a client's 540, the program just kept giving me an error on the FEIN line of the form (it was a valid FEIN, not an ITIN and I couldnt get it to take it), I ended up paper filing.

Oh wait, you said payee, my issue was with the withholding agents FEIN, sorry.

If its an SMLLC, didnt they apply for an EIN?  Thats what should be carrying over to the 592B, the EIN from the top of the 568 and the EIN at the top of the 568 carries over from the Federal Sch C thats been marked as a CA LLC at the top of the page.