How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix Unreal Blueprint Default Values Resetting After a Parent Recompile

Q: What causes Unreal Blueprint default values resetting after a parent recompile?

When a parent Blueprint or C++ class changes a property's type or default, the child instance's serialized override can no longer be applied and falls back to the new parent default.

Quick answer: Avoid changing property types on the parent without a redirect, recompile parents before children, and re-enter the child's overridden values after a breaking parent change so they re-serialize.

You set a custom default on a child Blueprint variable, but after recompiling the parent the child snaps back to the parent's value. The override could not survive the parent change.

How to fix it

1. Recompile in the right order

Compile and save the parent Blueprint or C++ class first, then open the child. Compiling children against a stale parent can drop overrides that no longer match the parent layout.

2. Avoid breaking type changes

Changing a variable's type or renaming it without a Core Redirect invalidates child overrides. Add a redirect in DefaultEngine.ini when you must rename, so serialized data still maps.

3. Re-apply and save overrides

After a breaking parent change, re-enter the desired default on the child and save so the override is serialized against the new parent definition.

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 Unreal Engine 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.

Most of the time the fix is small. Seeing the failure clearly is the part that actually costs you.