>fraud liability repayments (if the bank agrees to help) will take as long as the bank takes to recover funds

What's your source on that? As far as I know, Regulation E generally requires banks to make good on errors in electronic fund transfers (including ACH transfers for which the customer is not liable) within 10 days of being notified. That can be in the form of a provisional credit while an investigation is ongoing, though.

That's what makes this particularly galling since Zelle is just a frontend to ACH.

Is regulation E new (in the past decade)? I had a fraud related issue on Simple.com about 10 years back where Kroger decided to keep erratically billing my debit card up until it hit $1000 (I went in and spent probably $20 and their payments system seemed to just go haywire) and I asked their support for help. It took a month to get money back. That was my final straw with debit cards.

No; it's originally from the late 70s - I don't know exactly when the various provisions relating to error handling got introduced, to be honest; it's possible it was somewhat different back then.