Log in to Hearthstone to see if you were one of those affected.
Multiple Reddit users are reporting having received 2,000 Arcane Dust when logging in to Hearthstone. It is likely the reparations that Blizzard mentioned as part of a Pity Timer bug that may have cost users up to one Epic and on Legendary card. This makes sense considering those two cards combined would cost the full 2,000 dust.
Note: It is likely that the dust is rolling out over time, so don't panic if you haven't received it yet.
Blizzard has emailed those affected by the bug.
Here is the original confirmation of the bug:
4 hours ago
Hearthstone Patch 8.4 introduced new infrastructure to prepare for the recently announced improvements to card drop rates. An unexpected side effect of this change was that a small number of players who opened packs after the patch received one fewer Legendary or Epic card than they would have otherwise. We've identified the issue and expect it to be resolved next week. It's important to us that Hearthstone players feel great about opening card packs and we apologize for this issue and any disappointment that it may have caused. We will be reaching out to all affected players in the next few weeks with details regarding our resolution plan.