diff --git a/libs/ardour/plugin_insert.cc b/libs/ardour/plugin_insert.cc
index 0c76b65c84..5dd35c881c 100644
--- a/libs/ardour/plugin_insert.cc
+++ b/libs/ardour/plugin_insert.cc
@@ -1212,6 +1212,9 @@ PluginInsert::PluginControl::PluginControl (PluginInsert*                     p,
 {
 	if (alist()) {
 		alist()->reset_default (desc.normal);
+		if (desc.toggled) {
+			list->set_interpolation(Evoral::ControlList::Discrete);
+		}
 	}
 
 	if (desc.toggled) {
diff --git a/libs/evoral/src/ControlList.cpp b/libs/evoral/src/ControlList.cpp
index 8c98491638..2113755874 100644
--- a/libs/evoral/src/ControlList.cpp
+++ b/libs/evoral/src/ControlList.cpp
@@ -54,7 +54,7 @@ double ControlList::_thinning_factor = 20.0;
 
 ControlList::ControlList (const Parameter& id)
 	: _parameter(id)
-	, _interpolation(Linear)
+	, _interpolation(id.toggled() ? Discrete : Linear)
 	, _curve(0)
 {
 	_frozen = 0;