I mistakingly pulled a drive for a pool, pool showed degraded. I reinserted drive, pool never shows as healthy. Also, found the correct drive to pull (for another pool), pulled that drive, but that pool never shows as degraded. One pool it works on, the other it doesn't. Situation was resolved once I rebooted the system. Healthy drive showed healthy, degraded pool showed degraded.
Also, for the second drive I pulled, a spare was attached to that pool. Spare never integrated into the pool. Screenshot provided.