OK, some corrections to my previous post. After the drives turn amber, I am not able to access them. Not sure why I thought otherwise. I am able to access the admin app but the status shows no issues. Also, I am receiving email alerts that the drives have failed-- just had a config wrong so they were being rejected by my ISP.
Also, it seems like the lights turned amber at or just after midnight. This seems significant -- not sure how though.
If I reboot the device there's a lot of disk activity but it is available eventually until the next morning...