How to Fix a Mobile Game Rewarded Ad Granting the Reward Twice

Some players figure out they get double currency from one ad, and your economy inflates. The code grants in two callbacks that both fire for a completed view. Consolidate to a single idempotent grant.

How to fix it

1. Grant in one place only

Use the dedicated earned-reward callback (e.g. OnUserEarnedReward) as the single source of truth and remove any grant logic from OnAdClosed, which also fires on dismiss.

2. Use a one-shot flag

Set a boolean when you load the ad, clear it the moment you grant, and ignore any further grant attempt for that ad instance to make the operation idempotent.

3. Verify server-side if possible

For real-money or competitive economies, validate rewards through server-side verification so a duplicated or spoofed client callback cannot pay out.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every mobile error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.