diff --git a/R/PipeOpProxy.R b/R/PipeOpProxy.R
index 7b91ab9ec..43f5b1e7d 100644
--- a/R/PipeOpProxy.R
+++ b/R/PipeOpProxy.R
@@ -88,7 +88,7 @@ PipeOpProxy = R6Class("PipeOpProxy",
       # input can be a vararg input channel
       inname = if (innum) rep_suffix("input", innum) else "..."
       ps = ps(
-        content = p_uty(tags = c("train", "predidct", "required"), custom_check = function(x) {
+        content = p_uty(tags = c("train", "predidct", "required"), custom_check = crate(function(x) {
           # content must be an object that can be coerced to a Graph and the output number must match
           tryCatch({
             graph = as_graph(x)
@@ -104,7 +104,7 @@ PipeOpProxy = R6Class("PipeOpProxy",
             }
           },
           error = function(error_condition) "`content` must be an object that can be converted to a Graph")
-        })
+        }, .parent = topenv()))
       )
       ps$values = list(content = PipeOpFeatureUnion$new(innum = innum))
       super$initialize(id, param_set = ps, param_vals = param_vals,