diff --git a/R/check_dag.R b/R/check_dag.R
index 9bc9bcd8c..3d0ae3c2f 100644
--- a/R/check_dag.R
+++ b/R/check_dag.R
@@ -312,15 +312,13 @@ check_dag <- function(...,
     adjustment_set <- unlist(dagitty::adjustmentSets(dag, effect = x), use.names = FALSE)
     adjustment_nodes <- unlist(dagitty::adjustedNodes(dag), use.names = FALSE)
     minimal_adjustments <- as.list(dagitty::adjustmentSets(dag, effect = x))
-    collider <- adjustment_nodes[vapply(adjustment_nodes, ggdag::is_collider, logical(1), .dag = dag, downstream = FALSE)]
-    if (!length(collider)) {
+    collider <- adjustment_nodes[vapply(adjustment_nodes, ggdag::is_collider, logical(1), .dag = dag, downstream = FALSE)] # nolint
+    if (length(collider)) {
+      # if we *have* colliders, remove them from minimal adjustments
+      minimal_adjustments <- lapply(minimal_adjustments, setdiff, y = collider)
+    } else {
       # if we don't have colliders, set to NULL
       collider <- NULL
-    } else {
-      # if we *have* colliders, remove them from minimal adjustments
-      minimal_adjustments <- lapply(minimal_adjustments, function(ma) {
-        setdiff(ma, collider)
-      })
     }
     list(
       # no adjustment needed when
@@ -330,7 +328,7 @@ check_dag <- function(...,
       # incorrect adjustment when
       # - required is NULL and current adjustment not NULL
       # - OR we have a collider in current adjustments
-      incorrectly_adjusted = (is.null(adjustment_set) && !is.null(adjustment_nodes)) || (!is.null(collider) && collider %in% adjustment_nodes),
+      incorrectly_adjusted = (is.null(adjustment_set) && !is.null(adjustment_nodes)) || (!is.null(collider) && collider %in% adjustment_nodes), # nolint
       current_adjustments = adjustment_nodes,
       minimal_adjustments = minimal_adjustments,
       collider = collider