Monzo card declines in California

[tbutz (🏳️‍🌈 Producer of "low value commentary")]

I know that BART has been identified as an issue previously, see:

Monzo not accepted by BART (Bay Area Rapid Transit) in San Francisco

I was in SF a couple of weeks back and the BART ticket machines didn’t seem to like my Monzo card. Has anyone else encountered this, and if so, were you able to get it to work?

This might be helpful. In any event I’d always check the Wiki articles on here prior to using Monzo abroad. There are always quirks it seems.