Drive failure during rebuild?

My 5n2 is going through a rebuild (I swapped drives and also enabled dual redundancy). I am getting the message of a drive failure, but all lights are blinking green/yellow because it is rebuilding. How do I know which drive failed? When I click on each one individually, they all say “condition good”

It also says I am covered for one drive failure. So maybe I am getting this because the dual part is not yet done? It still has 25 hours according to dashboard.

Wow, 2 changed states at the same time? Brave move. It might have been better to swap out your HDD and complete the rebuild before enabling Dual Redundancy.
If not already, make or update your external backup of your data.