Polygons changed when the geom column is converted to text and then back to sfc

Dear list members,

I hope this message finds you well.
I submit to you a problem with which I have been struggling for several
days without finding the beginning of a solution.

I need (i) to convert the geom column of a sf object into text and
transform the sf object into a dataframe,
           (ii) then convert this dataframe back into an sf object.
My problem is that this only operation changes the shape of the original
polygons.
I guess the problem lies with the layer itself, but so far I haven't been
able to find the cause (the crs seems O.K., the geometry seems valid).

Please find attached a test layer containing only three contiguous
polygons and, below, the code needed to reproduce the problem :


test <- sf::st_read("Please add your path/polygons.gpkg")

# Converting the sf object into a dataframe with geom as text
test_chr <- test |>
  dplyr::mutate(geom = sf::st_as_text(geom, EWKT = TRUE)) |>
  as.data.frame()

# Converting back to a sf object
test_new <- test_chr |>
  dplyr::mutate(geom = sf::st_as_sfc(geom)) |>
  sf::st_sf()

# Comparing the original ('test') and the new ('test_new') sf objects
plot(test$geom, lwd = 1, border = "blue")
plot(test_new$geom, lwd = 2, lty = 2, border = "red", add = TRUE)


Thank you in advance for your help.
Cheers,
Lo?c