I assume it is the same issue than for priest and warlock due to the error on Bliz's side
Combatlog attached

What steps will reproduce the problem?
1. I pick a target and cast Arcane blast, the cast does 16997 damage.
2. The tier procs and 1 mirror image appears
3. I do not cast anymore and let my mirror image cast 2-3 times.
4. I go invisible to stop fight.

Combat log shows :

Gwen's AB does 16997 damage.
Gwen's Mirror image cast fireball for 7765 damages to ....
Gwen's Mirror image cast fireball for 6990 damages to ....
Gwen's Mirror image cast fireball for 7020 damages to ....

When I open Recount it only shows AB for 16997 damage.
Damage of the proc Mirror image doesn't appear and is not merged.

What is the expected output? What do you see instead?

Expected output would be:
  AB for 16997 damage
  Mirror images for 21775 damage

  or some form of merged damage.

What version of the product are you using?

Recount-v4.2.0f_release

Do you have an error log of what happened?

No error just an event not being tracked

Please provide any additional information below.

I will try to provide the exact combat log sentence.
repro is 100%