Niagara: error when using an expression

In Niagara I’m trying to use an expression in an Add Velocity module to check if a vector is not equal to 0 and based on that set the Add Velocity module’s value to another User variable, but I keep getting this error and I’m not sure what it means:

The Vector VM compile failed. Errors:
/Plugin/FX/Niagara/Private/NiagaraEmitterInstanceShader.usf(0): error: Component x of variable branch_flatten_temp has no valid offset. Possibly uninitialized data being used.
/Plugin/FX/Niagara/Private/NiagaraEmitterInstanceShader.usf(0): error: Component x of variable branch_flatten_temp has no valid offset. Possibly uninitialized data being used.
/Plugin/FX/Niagara/Private/NiagaraEmitterInstanceShader.usf(0): error: Component y of variable branch_flatten_temp has no valid offset. Possibly uninitialized data being used.
/Plugin/FX/Niagara/Private/NiagaraEmitterInstanceShader.usf(0): error: Component y of variable branch_flatten_temp has no valid offset. Possibly uninitialized data being used.

Here’s the expression I’m trying to use in the Add Velocity module: User.SmokeVelocityScale != float3(0,0,0) ? User.MaxWindVelocity : User.MaxVelocity

The variable User.SmokeVelocityScale gets set in code based on a value the user enters in a previous level, so when the new level begins if User.SmokeVelocityScale is not 0 set my velocity to User.MaxWindVelocity, otherwise set it to User.MaxVelocity. Any suggestions to fix the error is appreciated!

I meet same problm when i was trying to rebuild the first example in the Advanced Niagara Map which belongs to Example Content.