lvconvert asked to wipe an ext4 signature. I refused. But it says it succeeded. What's going on?

Question

I have a volume group hdd_encrypted_vg on two physical devices. I had a logical volume important in this vg on one of the physical devices. I wanted to make important a raid1, so I did lvconvert:

# lvconvert --type raid1 --mirrors 1 hdd_encrypted_vg/important
Are you sure you want to convert linear LV hdd_encrypted_vg/important to raid1 with 2 images enhancing resilience? [y/n]: y
WARNING: ext4 signature detected on /dev/hdd_encrypted_vg/important_rmeta_1 at offset 1080. Wipe it? [y/n]: n
  Aborted wiping of ext4.                                                 
  1 existing signature left on the device.                                
  Logical volume hdd_encrypted_vg/important successfully converted.

As you can see, it found some ext4 signature and asked me if I want to wipe it. I didn't know what's going on, so I answered no, but still lvconvert said that it has converted successfully. So I am afraid that some kind of wipe failed to happen, but lvconvert doesn't know about it, so my data is going to be corrupted. Is it?

Also, lvs said the copying (from one physical devices to the other, I assume) is currently going on:

# lvs -a -o name,copy_percent,devices hdd_encrypted_vg
  LV                    Cpy%Sync Devices                                    
  hdd_1tb_encrypted_vol          /dev/mapper/hdd_4tb_part_3tb_luks(710399)  
  hdd_1tb_encrypted_vol          /dev/mapper/hdd_4tb_part_3tb_luks(281600)  
  hdd_1tb_encrypted_vol          /dev/mapper/hdd_4tb_part_3tb_luks(128000)  
  important             19.66    important_rimage_0(0),important_rimage_1(0)
  [important_rimage_0]           /dev/mapper/hdd_4tb_part_3tb_luks(0)       
  [important_rimage_0]           /dev/mapper/hdd_4tb_part_3tb_luks(633599)  
  [important_rimage_1]           /dev/mapper/hdd_1tb_luks(1)                
  [important_rmeta_0]            /dev/mapper/hdd_4tb_part_3tb_luks(948865)  
  [important_rmeta_1]            /dev/mapper/hdd_1tb_luks(0)

Is my data corrupted or going to get corrupted? Do I need to cancel the copying, convert raid1 back to linear and redo it? If no, why did it even ask me about wiping?