diff --git a/src/libslic3r/PrintObject.cpp b/src/libslic3r/PrintObject.cpp
index 4dabfdd76..ff4233305 100644
--- a/src/libslic3r/PrintObject.cpp
+++ b/src/libslic3r/PrintObject.cpp
@@ -714,14 +714,13 @@ bool PrintObject::invalidate_state_by_config_options(
             steps.emplace_back(posPerimeters);
         } else if (opt_key == "gap_infill_speed" || opt_key == "filter_out_gap_fill") {
             // Return true if gap-fill speed has changed from zero value to non-zero or from non-zero value to zero.
-            // todo multi_extruders: Parameter migration between single and double extruder printers
             auto is_gap_fill_changed_state_due_to_speed = [&opt_key, &old_config, &new_config]() -> bool {
                 if (opt_key == "gap_infill_speed") {
-                    const auto *old_gap_fill_speed = old_config.option<ConfigOptionFloat>(opt_key);
-                    const auto *new_gap_fill_speed = new_config.option<ConfigOptionFloat>(opt_key);
+                    const auto *old_gap_fill_speed = old_config.option<ConfigOptionFloatsNullable>(opt_key);
+                    const auto *new_gap_fill_speed = new_config.option<ConfigOptionFloatsNullable>(opt_key);
                     assert(old_gap_fill_speed && new_gap_fill_speed);
-                    return (old_gap_fill_speed->value > 0.f && new_gap_fill_speed->value == 0.f) ||
-                           (old_gap_fill_speed->value == 0.f && new_gap_fill_speed->value > 0.f);
+                    return (old_gap_fill_speed->values.size() != new_gap_fill_speed->values.size())
+                        || (old_gap_fill_speed->values != new_gap_fill_speed->values);
                 }
                 return false;
             };