diff --git a/helper/schema/field_reader_diff.go b/helper/schema/field_reader_diff.go
index d558a5bc9..ae35b4a87 100644
--- a/helper/schema/field_reader_diff.go
+++ b/helper/schema/field_reader_diff.go
@@ -174,6 +174,9 @@ func (r *DiffFieldReader) readPrimitive(
 
 func (r *DiffFieldReader) readSet(
 	address []string, schema *Schema) (FieldReadResult, error) {
+	// copy address to ensure we don't modify the argument
+	address = append([]string(nil), address...)
+
 	prefix := strings.Join(address, ".") + "."
 
 	// Create the set that will be our result
diff --git a/helper/schema/field_reader_map.go b/helper/schema/field_reader_map.go
index 054efe08f..53f73b71b 100644
--- a/helper/schema/field_reader_map.go
+++ b/helper/schema/field_reader_map.go
@@ -98,6 +98,9 @@ func (r *MapFieldReader) readPrimitive(
 
 func (r *MapFieldReader) readSet(
 	address []string, schema *Schema) (FieldReadResult, error) {
+	// copy address to ensure we don't modify the argument
+	address = append([]string(nil), address...)
+
 	// Get the number of elements in the list
 	countRaw, err := r.readPrimitive(
 		append(address, "#"), &Schema{Type: TypeInt})