NAs Showing Up in Second Mean Column

Is this what you mean?

library(dplyr)

# Sample data on a copy/paste friendly format, replace this with your own data frame
pa_new1 <- data.frame(
  stringsAsFactors = FALSE,
        Start.Date = c("1974-08-02","1974-07-12",
                       "1974-06-28","1974-06-21","1974-05-31","1974-05-17"),
          End.Date = c("1974-08-05","1974-07-15",
                       "1974-07-01","1974-06-24","1974-06-03","1974-05-20"),
         Approving = c(24, 24, 28, 26, 28, 26),
      Disapproving = c(66, 63, 58, 61, 61, 61),
     Unsure.NoData = c(10, 13, 14, 13, 11, 13),
              Date = c("1974-08-02","1974-07-12",
                       "1974-06-28","1974-06-21","1974-05-31","1974-05-17"),
              year = c("1974", "1974", "1974", "1974", "1974", "1974"),
             month = c("08", "07", "06", "06", "05", "05")
)

# Relevant code
pa_new1 %>% 
    group_by(year, month) %>% 
    summarise(across(where(is.numeric), mean))
#> `summarise()` has grouped output by 'year'. You can override using the
#> `.groups` argument.
#> # A tibble: 4 × 5
#> # Groups:   year [1]
#>   year  month Approving Disapproving Unsure.NoData
#>   <chr> <chr>     <dbl>        <dbl>         <dbl>
#> 1 1974  05           27         61            12  
#> 2 1974  06           27         59.5          13.5
#> 3 1974  07           24         63            13  
#> 4 1974  08           24         66            10

Created on 2022-05-07 by the reprex package (v2.0.1)

Note: Next time please provide a proper REPRoducible EXample (reprex) illustrating your issue.