> it implies that employers wouldn't know that they'd be on the hook for unemployment deficits, despite it being an explicit part of a pretty-well trodden piece of federal law.

This is misleading- employers know they would need to pay for any deficits. But employers did not expect there to be deficits- no one expected that CA would default on the loan. And the reason why CA defaulted is frustrating:

"When states across the country received loan-free federal aid as a result of the federal government’s unprecedented emergency spending packages, most chose to use at least a portion of those funds to pay back the federal loans they’d been forced to take to support their unemployment programs. California received $15.3 billion in federal Coronavirus Relief Funds, *but allocated none of it to repaying its outstanding loans.*" [1]

The same article also points out that CA could have paid off the loan easily with their surplus ($97.5 billion)- but they simply decided not to...

> because "a maximum of $21" isn't quite as eye-popping as $18.5 billion

The issue is in the end, the $18.5 billion will all be paid off. It's still an extra $18.5 billion being paid that would not have been paid otherwise, if CA had been more responsible.

[1] https://www.ocregister.com/2023/03/27/california-had-a-97-5-...