Severe progressive FPS loss caused by “Use Latest HUD Elements” during weapon/pickaxe swapping

Summary

Description
I found a reproducible performance issue in UEFN where enabling Island Settings → User Interface → HUD → Use Latest HUD Elements causes severe FPS drops and hitching when repeatedly switching between a weapon and the pickaxe.

The issue occurred in my published island and in UEFN Launch Sessions. FPS initially remained near 240, but repeatedly swapping between a gun and pickaxe caused progressively worse frame drops, eventually falling below 100 FPS. Holding weapons, shooting, moving, and building did not cause the same degradation.

What Type of Bug are you experiencing?

Gameplay

Steps to Reproduce

Reproduction Steps
Open a UEFN island with an Island Settings device.
Set Use Latest HUD to On.
Launch a session.
Pick up any weapon.
Repeatedly switch between the weapon and pickaxe for approximately 30–90 seconds.
Observe increasing frame-time spikes, hitching, and progressive FPS loss.

Expected Result

Expected Result
Weapon and pickaxe switching should remain smooth with stable frame rate.

Observed Result

Observed Result
Each swap produces a small frame-time spike. Rapid repeated swapping causes progressively worse hitching and significant FPS degradation.

Affects Versions

5.8

Platform(s)

Windows

Additional Notes

Testing Completed

I ruled out Verse, class devices, item devices, inventory settings, player settings, world settings, matchmaking settings, water, barriers, teleporters, and other island devices.

Controlled results:

All original settings with Use Latest HUD Elements = On → issue occurs.
Resetting the HUD section to defaults → issue disappears.
Enabling only Use Latest HUD Elements again → issue returns.
Restoring every previous setting except Use Latest HUD Elements → issue remains completely fixed.

The issue was also fixed in the original production island, not only in test duplicates.

Current Workaround

Set Use Latest HUD Elements to Off.

This appears to be a HUD-related performance or state-refresh issue triggered by equipment-slot transitions.