diff --git a/R/layer.R b/R/layer.R
index d4396aeb4e..179f519441 100644
--- a/R/layer.R
+++ b/R/layer.R
@@ -974,7 +974,8 @@ normalise_label <- function(label) {
   if (obj_is_list(label)) {
     # Ensure that each element in the list has length 1
     label[lengths(label) == 0] <- ""
-    label <- lapply(label, `[`, 1)
+    truncate <- !vapply(label, is.call, logical(1)) # Don't mess with call/formula
+    label[truncate] <- lapply(label[truncate], `[`, 1)
   }
   if (is.expression(label)) {
     # Classed expressions, when converted to lists, retain their class.
diff --git a/R/position-.R b/R/position-.R
index 845b095862..4f3008c725 100644
--- a/R/position-.R
+++ b/R/position-.R
@@ -102,6 +102,10 @@ Position <- ggproto(
   #' A data frame with completed layer data
   use_defaults = function(self, data, params = list()) {
 
+    if (empty(data)) {
+      return(data)
+    }
+
     aes <- self$aesthetics()
     defaults <- self$default_aes
 
@@ -113,6 +117,13 @@ Position <- ggproto(
       return(data)
     }
 
+    empty_aes <- names(params)[lengths(params) == 0]
+    if (length(empty_aes) > 0) {
+      # The Geom$use_defaults method will already warn about this, we just need
+      # to ignore this here.
+      params <- params[setdiff(names(params), empty_aes)]
+    }
+
     new <- compact(lapply(defaults, eval_tidy, data = data))
     new[names(params)] <- params
     check_aesthetics(new, nrow(data))
diff --git a/R/stat-align.R b/R/stat-align.R
index 7278773cf3..c0807382c7 100644
--- a/R/stat-align.R
+++ b/R/stat-align.R
@@ -77,7 +77,7 @@ StatAlign <- ggproto(
 
   finish_layer = function(data, params) {
     # Silently remove out-of-bounds padding vertices
-    var <- flipped_names(params$flipped_aes)$x
+    var <- flipped_names(params$flipped_aes %||% FALSE)$x
     remove <- is.na(data[[var]]) & (data$align_padding %||% FALSE)
     vec_slice(data, !remove)
   }