R shinyapps won't deploy: "Error in value[[jvseq[[jjj]]]] : subscript out of bounds"

The app runs fine locally. It uses a series of sliders to form a reactive i.e.

block_data <<- reactive({blocks %>% 
            filter(pred_percentile >= input$pred_slider[1] & pred_percentile <= input$pred_slider[2] 
                   & crime_percentile >= input$crime_slider[1] & crime_percentile <= input$crime_slider[2]
                   & housing_percentile >= input$housing_slider[1] & housing_percentile <= input$housing_slider[2]
                   & traffic_percentile >= input$traffic_slider[1] & traffic_percentile <= input$traffic_slider[2]
            )
})

Anyone run into this issue before? Again, works fine locally, and then I receive the error message immediately when trying to deploy.