Touch Checksum mismatch on Read-back from uSD

[1]Used Win32-Imager to make an image of the internal SD card
[2] Copied the image into a new card
[3] Immediately read back from new card into another image file.
[4] Compared the MD5 checksums of the two images -- they do not match.

Is this normal? ... Or, it corrupted data waiting to brick my Kobo whenever it hits the bad part? [Note that the new card does work on the device, only much slower].

Thanks,
Swamp Thing