Quick answer: Unreal Niagara multi-mesh renderer drawing wrong mesh after enabling/disabling? Binding order in inspector doesn't match runtime order - explicitly set Mesh Index per particle.
VFX has 3 mesh variants. Particles ping-pong between them seemingly at random instead of using the inspector-listed defaults.
Set Mesh Index attribute
Particle attribute MeshIndex. Set per-particle in the Initialize module. Explicit; doesn't depend on render order.
Or split into separate emitters
One emitter per mesh variant. Cleaner; small overhead; no binding bugs.
Verify with the Niagara debugger
FX > Debugger. Per-particle mesh index visible; mismatches diagnose the binding state.
“Multi-mesh renderers have rules. Explicit attributes are safer than implicit defaults.”
For VFX with mesh variation, prefer separate emitters when the variants differ significantly. Multi-mesh is for color/scale; not for different shapes.