How should be interpret these statistics

Your software
My Mautic version is: 4

We’ve sent out an email with 2 versions:

  • Numbers from main overview: Sent: 26,712 (50/50 Split, so 13,356 Sends for each Variant), Read: 9,652

Reads by variants: A: 9,579, B: 4,689

“Devices” - A Variant:

  • Desktop: 11,064
  • Smartphone: 919
  • Unknown: 7,335

“Devices” - B Variant:

  • Desktop: 5,389
  • Smartphone: 425
  • Unknown: 3,607

For what I’ve read, the “Unknown” should be ignored. That’s being triggered by mail clients scanning the emails. Right?

The stats about the device are email reads on a specific device, no? So why do those numbers not match the total read count of the separate emails?
The A variant has almost 12K in type of device but only 9,5K reads.

How does this work?