Although this was not reported on the status dashboard, this also affected elasticcache as well.It was acknowledged by the rep on the phone and via email issue

Although this was not reported on the status dashboard, this also affected elasticcache as well.It was acknowledged by the rep on the phone and via email issue got resolved. We weren't able start/reboot any redis instances on us-east-1a so had to launch on us-east-1c.