>Signal when you change lanes or exit the roundabout.

California Driver Handbook

https://www.dmv.ca.gov/web/eng_pdf/dl600.pdf

Roundabouts are a one way road, you don´t need to signal when driving on it. But you do need to indicate when you are leaving the roundabout.

Might be a regionalism, but here in Oregon, we don't signal going in, but signal right before we intend to exit. That way the next incoming driver can enter the roundabout and keep traffic flowing. We have a LOT of roundabouts though, like dozens upon dozens, and many of them are over saturated. It may be a local response to the traffic patterns here, not sure.

The most important thing is for everyone to speak the same protocol, provided that the protocol meets some minimum standard of fitness-for-purpose. But… yeah, I think you're doing it wrong.