[R-sig-Geo] Error in impacts() after lagsarlm (spdep package)

[Denys Dukhovnov]

I posted this question on StackOverflow a while back but received no answer. 

I have 9,150 polygons in my data set. I was trying to run a spatial autoregressive model (SAR) in spdep to test spatial dependence of my outcome variable. After running the model, I wanted to examine the direct/indirect impacts, but encountered an error that seems to have something to do with the length of neighbors in the weights matrix not being equal to n. I tried running the very same equation as SLX model (Spatial Lag X), and impacts() worked fine, even though there were some polygons in my set that had no neighbors. 

> # Defining queen contiguity neighbors for polyset and storing the matrix as list
> q.nbrs <- poly2nb(polyset) 
> listweights <- nb2listw(q.nbrs, zero.policy = TRUE)

> # Defining the model
> model.equation <- TIME ~ A + B + C

> # Run SAR model
> reg <- lagsarlm(model.equation, data = polyset, listw = listweights, zero.policy = TRUE)

> # Run impacts() to show direct/indirect impacts
> impacts(reg, listw = listweights, zero.policy = TRUE)

> Error in intImpacts(rho = rho, beta = beta, P = P, n = n, mu = mu, Sigma = Sigma,  : 
    length(listweights$neighbours) == n is not TRUE

What am I doing wrong? I am running Windows 10 machine with R 3.5.3 with the most up-to-date spdep package, if it helps.

Thank you very much.

Regards,
Denys Dukhovnov