Okay so I figured out that my problem was that my reactive list1 and list2 were vectors and not data tables. Thus I converted the output to a table and it works perfectly now!
list1 <- reactive({
v <- sample_df %>% filter(region == input$region) %>% filter(numbers != "00000")
v$numbers %>% unique() %>% as.tibble()
})
list2 <- reactive({
v <- sample_df %>% filter(subregion == input$subregion) %>% filter(numbers != "00000")
v$numbers %>% unique() %>% as.tibble()
})