(Source)

The PTR has been updated with the following change to Frost Mage:

CLASSES

• Mage
  • Frost
    • Reverted the recent change that added an internal cooldown to the Icy Propulsion conduit.
    • Frozen Orb damage reduced by 12% (was 8%).
    • Blizzard damage reduced by 12% (was 5%) and reduces the cooldown of Frozen Orb by 0.25 seconds each time Blizzard deals damage (was 0.5 seconds).
      • Developers’ note: After further consideration we will be reverting the Icy Propulsion internal cooldown (ICD) change and instead further reduce the damage of Frozen Orb and Blizzard. Our goal with the initial change to the internal cooldown was to help curb some of the power it’s gained over the expansion from other bonuses and changes such as the uncapping of Frozen Orb, the upcoming tier set bonus, and ilvl increase of the conduit itself. However, we recognize that the Icy Veins uptime it has provided as the expansion progressed is something that Frost Mages have grown accustomed to and losing that power in 9.2 will end up feeling like a regression in both performance and enjoyment of how the spec plays.