Interactive Shiny Leaflet Map with "Error in : Must subset rows with a valid subscript vector"

[dysonsphere]

Hi,
I am working on creating an interactive map to visualize geographical drafting trends in the NHL.
I am working off my R knowledge as well as the example of a Shiny interactive map detailed here: https://www.shafquatarefeen.com/r-shiny-permits/
My Leaflet code works to create the map fine outside the Shiny environment:

bio_leaflet <- leaflet(bio_data) %>% setView(lng = -10, lat = 45, zoom = 2) %>%
  addProviderTiles(providers$CartoDB.Positron) %>%
  addMarkers(
    clusterOptions = markerClusterOptions(),
    #color = ~pal(first_season),
    lng = bio_data$lon, lat = bio_data$lat, # designate the lon and lat values to be plotted as markers on the map
    icon = stick_puckIcon,
    popup = paste("Player:", bio_data$Player, "<br>",
                  "Born in: ", bio_data$origin, "<br>",
                  "Born on: ", bio_data$DOB, "<br>",
                  "Draft Year: ", bio_data$draft_year, "<br>",
                  "Round: ", bio_data$Round, "<br>",
                  "Overall: ", bio_data$Overall, "<br>",
                  "NHL Debut: ", bio_data$first_season
                  ));

However, when I try to get it to work within a Shiny app I get the following error message:

Listening on http://127.0.0.1:6937
Warning: Error in : Must subset rows with a valid subscript vector.
Logical subscripts must match the size of the indexed input.
x Input has size 7167 but subscript rows has size 0.
115:
Warning: Error in : Must subset rows with a valid subscript vector.
Logical subscripts must match the size of the indexed input.
x Input has size 7167 but subscript rows has size 0.
112:

My Shiny code:

stick_puckIcon <- makeIcon(
  iconUrl = "~/Nextcloud/dysoncloud/Projects/data_vis/origins/stick_puck.png",
  iconWidth = 50, iconHeight = 50,
  iconAnchorX = 22, iconAnchorY = 94)

ui <- fluidPage(
sidebarPanel( # selection panel
  sliderInput(inputId = "debut", # slider to choose range of years for debut NHL season
              label = "Choose a Range of NHL Debut Years",
              min=1917,
              max=2019,
              value=c(1917, 2019),
              sep = ""),
  selectInput(inputId = "country", # selection box to pick a specific country
              label = "Choose a Country of Origin",
              choices = c("All", sort(unique(as.character(bio_data$Ctry))))),
  selectInput(inputId = "position", # selection box to pick a specific position
              label = "Choose Position",
              choices = c("All", sort(unique(as.character(bio_data$Pos)))))
),
mainPanel(
  leafletOutput("bio_leaflet", height = 1040) # panel for the map to render
))


server <- function(input, output, session){
  filtered_map <- reactive({ # generate filtered map for the inputs from the selection panel in the ui
    rows <- bio_data$first_season<=input$debut[2] & bio_data$first_season>=input$debut[1] &
      (input$country == "All" | bio_data$Ctry==input$country) &
      (input$position == "All" | bio_data$Pos==input$postition)
    bio_data[rows,,drop = FALSE]  # remove NULL data, without this line I get "Warning: Error in $: $ operator is invalid for atomic vectors [No stack trace available]"
  })
  
  observeEvent( # observe the events in the input frames
    input$debut,{
      updateSelectInput(session,"country",choices=c("All", sort(unique(as.character(filtered_map()$country)))))
      updateSelectInput(session,"position",choices=c("All", sort(unique(as.character(filtered_map()$position)))))
    })
  output$bio_leaflet <- renderLeaflet({ # output the map and markers based on the filtered_map data
    leaflet() %>%
      setView(lng = -10, lat = 45, zoom = 3) %>%
      addProviderTiles(providers$CartoDB.Positron) %>%
      addMarkers(lng = filtered_map()$lon, lat = filtered_map()$lat, # designate the lon and lat values to be plotted as markers on the map
                 icon = stick_puckIcon, # use the icon defined above
                 popup = paste("Player:", bio_data$Player, "<br>", # paste various data on the icon popups
                  "Born in: ", bio_data$origin, "<br>",
                  "Born on: ", bio_data$DOB, "<br>",
                  "Draft Year: ", bio_data$draft_year, "<br>",
                  "Round: ", bio_data$Round, "<br>",
                  "Overall: ", bio_data$Overall, "<br>",
                  "NHL Debut: ", bio_data$first_season),
                 clusterOptions = markerClusterOptions() # cluster markers close to each other
      )
    })
}

shinyApp(ui = ui, server = server)

I am not sure where I am going wrong. I do not think it has to do with NULL data (there are missing data in the original data frame) as I have a line that removes NULLs in the from the filtered map without which I get: "Warning: Error in : operator is invalid for atomic vectors [No stack trace available]".
Any incites welcome.
Thanks