addDrawToolbar in modules throws TypeError: t is undefined

[trafficonese]

By using the addDrawToolbar in shiny modules on different tabs, the following Javascript error comes up in the console.

TypeError: t is undefined leaflet.js:5:10033

To trigger the error, start the app, go to Tab "mod2" and back to "mod1" and click on the map. Every interaction with the map will cause another console error.

shinyApp

  ## libs & data ###################################
  library(shiny)
  library(sf)
  library(leaflet)
  library(leaflet.extras)
  drawtoolbar = TRUE
  
  sfdata <- sf::st_as_sf(breweries91, coords="coordinates")
  
  ## modules ###################################
  mod1_ui <- function(id, label, value) {
    ns <- NS(id)
    tabPanel(label, value = value, leafletOutput(ns("map"))
    )
  }
  mod1_server <- function(input, output, session, parent_session, navid) {
    output$map <- renderLeaflet({
      req(parent_session$input$navbarid == navid)
      p <- leaflet() %>%
        addTiles()
      
      if (drawtoolbar) {
        p <- p %>% addDrawToolbar(position="topright",
                                  targetGroup = "Sel")
      }
      
      p
    })
  }
  
  ## ui ###################################
  ui <- navbarPage(id = "navbarid", title = 'DEMO', selected = 1,
                   mod1_ui("mod1", "mod1", 1),
                   mod1_ui("mod2", "mod2", 2)
  )
  
  ## server ###################################
  server <- function(input, output, session) {
    callModule(mod1_server, "mod1", parent_session = session, navid = 1)
    callModule(mod1_server, "mod2", parent_session = session, navid = 2)
  }
  
  ## Run App ###################################
  shinyApp(ui, server)

Interestingly, the error disappears when the following line in renderLeaflet is removed:
req(parent_session$input$navbarid == navid)

[trafficonese]

related rstudio/leaflet#657