diff --git a/NEWS.md b/NEWS.md
index 44bab132e..f1b5aae2f 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -2,6 +2,8 @@
 
 ## Bug fixes
 
+* `card()` and `value_box()` no longer register `input$<id>_full_screen` for cards that don't have `full_screen = TRUE`, avoiding unexpected inputs in bookmarking workflows. (#1305)
+
 * Fixed label-to-options spacing on `shiny::radioButtons()` and `shiny::checkboxGroupInput()` in Bootstrap 5, where a Shiny rule was overriding the bslib fix. (#1308)
 
 # bslib 0.11.0
diff --git a/R/card.R b/R/card.R
index 90498f82a..71645a9eb 100644
--- a/R/card.R
+++ b/R/card.R
@@ -26,10 +26,9 @@
 #'   together into one `wrapper` call (e.g. given `card("a", "b",
 #'   card_body("c"), "d")`, `wrapper` would be called twice, once with `"a"` and
 #'   `"b"` and once with `"d"`).
-#' @param id Provide a unique identifier for the `card()` or `value_box()` to
-#'   report its full screen state to Shiny. For example, using `id = "my_card"`,
-#'   you can observe the card's full screen state with
-#'   `input$my_card_full_screen`.
+#' @param id A unique identifier for the card. Note that full-screen
+#'   capability cannot be added after card creation; `full_screen` must be set
+#'   at creation time.
 #'
 #' @return A [htmltools::div()] tag.
 #'
@@ -90,7 +89,11 @@ card <- function(
   children <- as_card_items(args[!nzchar(argnames)], wrapper = wrapper)
   children <- card_image_add_classes(children)
 
-  is_shiny_input <- !is.null(id)
+  # When full_screen=TRUE and id is provided, the card registers
+  # input$<id>_full_screen to report its full screen state to Shiny.
+  # The bslib-card-input class is what triggers this JS-side registration,
+  # so it must only be added when the card actually has full screen capability.
+  is_shiny_input <- !is.null(id) && full_screen
 
   if (full_screen && is.null(id)) {
     # a11y: full screen cards need an ID for aria-controls on the toggle button
diff --git a/R/sysdata.rda b/R/sysdata.rda
index c20a80987..07bacd4a9 100644
Binary files a/R/sysdata.rda and b/R/sysdata.rda differ
diff --git a/man/card.Rd b/man/card.Rd
index 06f81f4be..ebb90602d 100644
--- a/man/card.Rd
+++ b/man/card.Rd
@@ -42,10 +42,9 @@ arguments in \code{...} which are not already card item(s) (like
 together into one \code{wrapper} call (e.g. given \code{card("a", "b", card_body("c"), "d")}, \code{wrapper} would be called twice, once with \code{"a"} and
 \code{"b"} and once with \code{"d"}).}
 
-\item{id}{Provide a unique identifier for the \code{card()} or \code{value_box()} to
-report its full screen state to Shiny. For example, using \code{id = "my_card"},
-you can observe the card's full screen state with
-\code{input$my_card_full_screen}.}
+\item{id}{A unique identifier for the card. Note that full-screen
+capability cannot be added after card creation; \code{full_screen} must be set
+at creation time.}
 }
 \value{
 A \code{\link[htmltools:div]{htmltools::div()}} tag.
diff --git a/man/value_box.Rd b/man/value_box.Rd
index db141db38..1117d80a7 100644
--- a/man/value_box.Rd
+++ b/man/value_box.Rd
@@ -90,10 +90,9 @@ container with an opinionated height (e.g., \code{page_fillable()}).}
 card. Use \verb{bg-*} and \verb{text-*} classes (e.g, \code{"bg-danger"} and
 \code{"text-light"}) to customize the background/foreground colors.}
 
-\item{id}{Provide a unique identifier for the \code{card()} or \code{value_box()} to
-report its full screen state to Shiny. For example, using \code{id = "my_card"},
-you can observe the card's full screen state with
-\code{input$my_card_full_screen}.}
+\item{id}{A unique identifier for the card. Note that full-screen
+capability cannot be added after card creation; \code{full_screen} must be set
+at creation time.}
 
 \item{theme_color}{\ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} Use \code{theme} instead.}
 
diff --git a/tests/testthat/test-card.R b/tests/testthat/test-card.R
index f782639a4..289c63686 100644
--- a/tests/testthat/test-card.R
+++ b/tests/testthat/test-card.R
@@ -40,6 +40,20 @@ test_that("card_image()", {
   )
 })
 
+test_that("card() only registers as Shiny input when full_screen=TRUE", {
+  card_no_fs <- card(id = "my_card", "content")
+  card_with_fs <- card(id = "my_card", full_screen = TRUE, "content")
+  card_fs_no_id <- card(full_screen = TRUE, "content")
+
+  classes_no_fs <- htmltools::tagGetAttribute(card_no_fs, "class")
+  classes_with_fs <- htmltools::tagGetAttribute(card_with_fs, "class")
+  classes_fs_no_id <- htmltools::tagGetAttribute(card_fs_no_id, "class")
+
+  expect_no_match(classes_no_fs, "bslib-card-input")
+  expect_match(classes_with_fs, "bslib-card-input")
+  expect_no_match(classes_fs_no_id, "bslib-card-input")
+})
+
 test_that("card_image() input validation", {
   expect_snapshot(
     error = TRUE,