v40.00 Known Issues

General Issues and Bug Reporting
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Hello Fortnite developers,

During pre-release testing for v40.00, our expanded testing process helped us to identify a number of issues that were fixed before the build was finalized for distribution. However, a few issues were discovered either too late in the cycle, or had to be delayed in favor of more critical issues.

Our goal is to get this list to zero for each new release, but while we work towards that, we want to make sure that developers are armed ahead of time with knowledge of upcoming regressions. Going forward, we’ll continue to share significant known issues in advance of releases, and will aim to do so earlier in the process, giving you the maximum time to prepare.

We know that some of these issues will be disruptive to your development work, and we’re putting processes in place for each new issue to ensure they won’t show up on this list on a future release.

We’ll update this thread as fixes roll out or timelines change. We’ve also included the list of top community requested fixes for pre-existing issues shipping with v40.00.

You can read more about the steps we’re taking to improve UEFN stability and iteration times here.

v40.00 Known Issues:

Unreal Revision Control (URC) Downtime

  • We expect roughly 2 hours of downtime for URC while we deploy backend improvements

  • URC downtime is expected to begin ~2 hours before Fortnite downtime ends for the v40.00 release

  • We’ll update this thread at the beginning and conclusion of URC downtime

Inconsistency in Texture Rendering Causing Black Flickering

  • A rendering change in this update causes visible black flickering across building surfaces, walls, and props in some islands, particularly those with dense or overlapping geometry

  • The issue is most noticeable while moving through the environment

  • Platforms: PC and console. Mobile is unaffected

  • Fix targeted for v40.20 (April 16)

Barrier Device May Not Render Correctly

  • The Barrier device may not render correctly on some islands which could impact the visibility of in-game boundaries

  • Fix targeted for v40.20 (April 16)

Building Materials Not Displaying in UI on Some Islands

  • In some islands that have building enabled, the materials resource UI may not appear, preventing players from seeing their current material counts

  • Players can still gather and build, but may run out of materials unexpectedly while building

  • Players respawning may resolve the issue

  • Fix targeted for v40.10 (April 1)

Assets Using ObjectPosition Material Node May Appear Offset or Displaced

  • Assets using the ObjectPosition material expression may render in incorrect positions

  • This can manifest as misplaced props, UI elements clipping into the ground, or items appearing offset from surfaces

  • Workaround: Replace ObjectPosition references in affected asset materials with TransformPosition and optionally, a Vector Parameter

  • Fix targeted for v40.20 (April 16)

Text Chat Unavailable on Switch, iOS and Android

  • Text chat cannot be opened during matches on developer-made islands on some platforms

  • Players can still communicate via voice chat

  • Platforms: Switch, Switch 2, Android, and iOS

  • Fix targeted for v40.10 (April 1)

Player Icon Not Updating in Some UIs When Changing Outfits

  • On some islands, the player icon displayed in custom UI elements may not update when changing outfits using the Phone Booth device

  • This is a UI-only issue; outfits update correctly in-game

  • Fix targeted for v40.20 (April 16)

Chance of Movement Lag When Sprinting

  • Sprinting may cause increasing lag on some islands, particularly when moving at high speed near large numbers of props and materials

  • Fix targeted for v40.10 (April 1)

Editor Crash When Placing D-Launcher Device

  • Placing a D-Launcher device on an island in UEFN may cause the editor to crash

  • This issue does not impact live islands

  • Workaround: Avoid placing this device after v40.00 until the fix is available

  • Fix targeted for v40.10 (April 1)

v40.00 Top Community Fixes

The following fixes address issues you submitted to us on the forums. Thank you for your patience and for reporting these issues!

  • Fixed the issue where projects that were within performance and memory limits were receiving “Cooker Out of Memory” and “Cook Timeout” errors.

  • Fixed an issue where adding a new mesh component would not update the mesh.

  • Fixed an issue where the prefab editor would crash when viewing certain prefabs.

  • Fixed an issue where rafting resources failed to display permanently on the HUD when enabling the Show Crafting Resources option.

  • Fixed an issue where NPC Character Definition Sessions were not updating NPC Spawners after pushing changes.

  • Fixed an issue where Proximity chat was not properly attenuating other clients’ voices based on distance.

For a full list of all scheduled fixes for 40.00, please refer to this search on the Epic Developer Community Forums.