@ramsey Sure, that's possible. I'll check if PDO avoids the issue, but a glance at the docs seems like ATTR_TIMEOUT doesn't make a connection / read distinction for MySQL either.
The bug report proposes a reasonable change of including the max-time-to-first-byte in the connection timeout so connect/read are properly decoupled. RDS has had this issue a few times (probably load balancer related).
Cerb is likely older than PDO, so that's not an easy change. I'd break more than I fix. 😅