Raid 1 clean after recovery but is it?

I am running Raid 1 on OMV 6.9.0-1 (Shaitan)

Following a major power supply failure (some kind of short circuit, melted cables ) my system disk and one of the Raid 1 disks were invisible to BIOS. I believed that the second Raid 1 disk might still have data and be accessible.

After lots of testing to verify M/B and other components still ok I attempted to recover my data from the remaining Raid 1 disk. First step recover my OMV system from backup onto a new disk. I was then able to see all shared folder etc but Raid 1 was missing in the Raid tab.

So I reconnected the (maybe) good drive and looking via terminal I found that MDSTAT showed that the Raid 1 has a single element with persistent superblock but was inactive. Using the MDADM -R command started the raid and it became visible in the OMV Raid tab obviously degraded.

Shutdown and reconnect a totally different drive that had been used the same Raid setup in the past (a backup drive if you will). On power up Raid array is back up and running with the Raid tab showing two disks and clean. There was no resyncing or rebuilding just immediately clean.

How can the raid be clean since the raid was in frequent use before the failure and the backup disk has not been used for more than a year? Can I trust that the data is actually in tact? Wonder If I should remove the backup disk, erase it and the add it back to the array to force a rebuild?

I would appreciate your comments

root@omv-bowstones:/# mdadm -D /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Thu Nov 17 23:38:29 2022
        Raid Level : raid1
        Array Size : 976630464 (931.39 GiB 1000.07 GB)
     Used Dev Size : 976630464 (931.39 GiB 1000.07 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Fri Sep 29 15:34:15 2023
             State : clean 
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : bitmap

              Name : OMV-Bowstones:0
              UUID : d54bf475:8bff05da:6a6133f0:694fed81
            Events : 2924

    Number   Major   Minor   RaidDevice State
       0       8        0        0      active sync   /dev/sda
       1       8       16        1      active sync   /dev/sdb

root@omv-bowstones:/# blkid
/dev/sdb: UUID="d54bf475-8bff-05da-6a61-33f0694fed81" UUID_SUB="e84b14be-902b-b4bc-bf2c-f1bdb792fddb" LABEL="OMV-Bowstones:0" TYPE="linux_raid_member"
/dev/sda: UUID="d54bf475-8bff-05da-6a61-33f0694fed81" UUID_SUB="5466540a-4f49-680f-c505-a552adb6a49b" LABEL="OMV-Bowstones:0" TYPE="linux_raid_member"
/dev/sdc1: UUID="bda434a2-8366-4a75-b70f-16b78265e64c" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="ef8f51c6-01"
/dev/sdc5: UUID="ce799b4d-d1f1-452d-b445-0e6aa6a97109" TYPE="swap" PARTUUID="ef8f51c6-05"
/dev/md0: UUID="865fd172-e7e6-47ef-9dc1-e9f199389a06" BLOCK_SIZE="4096" TYPE="ext4"

root@omv-bowstones:/# cat /proc/mdstat
Personalities : [raid1] [linear] [multipath] [raid0] [raid6] [raid5] [raid4] [raid10] md0 : active raid1 sda[0] sdb[1] 976630464 blocks super 1.2 [2/2] [UU] bitmap: 3/8 pages [12KB], 65536KB chunk
unused devices: