How to Fix a Mulligan Drawing Duplicate Cards in a Card Game

If a mulligan can hand you two copies of a one-of card, your draw and return order is wrong. Cards must go back before they can come out again. Here is the correct sequence.

How to fix it

1. Return before reshuffle

Move every card from the current hand back into the deck collection first, so the deck once again contains the entire library.

2. Reshuffle the whole deck

Run your unbiased shuffle over the recombined deck. Now the redraw samples from a deck where each card appears exactly once.

3. Draw the new hand last

Only after return and reshuffle do you draw the replacement hand. For partial mulligans, return just the chosen cards and draw the same count back.

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 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.