The proper way to codify Na in a list in R

Question

I am trying to impute missing timeseries present in different dimentions, row by row, on the whole date set. I showed the type of return of na.kalman() and it happens to be a tribble, I am not so keen on R, so I thought converting it to a plain vector will do it, something like array(as.data.frame(imputed_slice))

library("imputeTS")
library(readr)

slice <- read_csv("slice.csv")
little_slice <- slice[c(750: 850)]
for (row in 1:nrow(little_slice)) {
  ts <- little_slice[row,]
  if(any(is.na(ts)))
     {
       imputed_ts <- na.kalman(ts, model = "auto.arima")
       little_slice[row,] <- array(imputed_ts)
  }
}

#529, 811, 812 missings

Looking for warning, I see something like:

imputeTS: No imputation performed for column 64 because of this Error in na.kalman(data[, i], model, smooth, nit, ...): Input data needs at least 3 non-NA data point for applying na.kalman

For every row, so I tried to force other columns to be NA

Like this:

slice$`811` <- NA
slice$`812` <- NA
slice$`822` <- NA
slice$`832` <- NA

To sum up, why na.kalman() not recognizing my NAs?