Error Building Rstanarm to Shiny

[LPA]

Cannot build an app using rstanarm on Shiny that works fine locally and that worked three weeks ago building to Shiny. Since a few weeks ago when I could build rstanarm apps to Shiny, I've had the latest updates to Windows 10 which is when I noticed I could no longer build to Shiny.

Since those Windows updates I've also updated R to 4.0.5 and RStudio to 1.4.1106. Package versions are: Rstan 2.21.2, Rstanarm 2.21.1, Rcpp 1.0.6, RcppEigen 0.3.3.9.1.

Example - I added library(rstanarm) to the top of the default Shiny app template in RStudio for Windows and got the same error. Code and error follow.

library(shiny)
library(rstanarm) # I added this as test

Define UI for application that draws a histogram

ui <- fluidPage(

# Application title
titlePanel("Old Faithful Geyser Data"),

# Sidebar with a slider input for number of bins 
sidebarLayout(
    sidebarPanel(
        sliderInput("bins",
                    "Number of bins:",
                    min = 1,
                    max = 50,
                    value = 30)
    ),

    # Show a plot of the generated distribution
    mainPanel(
       plotOutput("distPlot")
    )
)

)

Define server logic required to draw a histogram

server <- function(input, output) {

output$distPlot <- renderPlot({
    # generate bins based on input$bins from ui.R
    x    <- faithful[, 2]
    bins <- seq(min(x), max(x), length.out = input$bins + 1)

    # draw the histogram with the specified number of bins
    hist(x, breaks = bins, col = 'darkgray', border = 'white')
})

}

Run the application

shinyApp(ui = ui, server = server)

Here's the bottom of the deployment log:
/opt/R/4.0.5/lib/R/library/RcppEigen/include/Eigen/src/Core/ProductEvaluators.h:383:34: [ skipping 14 instantiation contexts, use -ftemplate-backtrace-limit=0 to disable ]
/opt/R/4.0.5/lib/R/library/RcppEigen/include/Eigen/src/Core/ProductEvaluators.h:251:23: required from ‘static void Eigen::internal::generic_product_impl<Lhs, Rhs, Eigen::DenseShape, Eigen::DenseShape, 6>::evalTo(Dst&, const Lhs&, const Rhs&) [with Dst = Eigen::Matrix<double, 1, 1, 0, 1, 1>; Lhs = Eigen::Product<Eigen::CwiseBinaryOp<Eigen::internal::scalar_product_op<double, double>, const Eigen::CwiseNullaryOp<Eigen::internal::scalar_constant_op, const Eigen::Matrix<double, 1, -1> >, const Ei################################# End Task Log #################################
Error: Unhandled Exception: Child Task 909051226 failed: Error building image: Error building rstanarm (2.21.1). Build exited with non-zero status: 1
Execution halted