diff --git a/src/libslic3r/Print.cpp b/src/libslic3r/Print.cpp
index 6126af162..c423afeb9 100644
--- a/src/libslic3r/Print.cpp
+++ b/src/libslic3r/Print.cpp
@@ -502,7 +502,10 @@ void Print::config_diffs(
 	        const ConfigOption *opt_old = m_config.option(opt_key);
 	        assert(opt_old != nullptr);
 	        const ConfigOption *opt_new = new_full_config.option(opt_key);
-	        assert(opt_new != nullptr);
+			// assert(opt_new != nullptr);
+			if (opt_new == nullptr)
+				//FIXME This may happen when executing some test cases.
+				continue;
 	        const ConfigOption *opt_new_filament = std::binary_search(extruder_retract_keys.begin(), extruder_retract_keys.end(), opt_key) ? new_full_config.option(filament_prefix + opt_key) : nullptr;
 	        if (opt_new_filament != nullptr && ! opt_new_filament->is_nil()) {
 	        	// An extruder retract override is available at some of the filament presets.
@@ -575,12 +578,11 @@ Print::ApplyStatus Print::apply(const Model &model, DynamicPrintConfig new_full_
     // which should be stopped if print_diff is not empty.
     if (! full_config_diff.empty() || ! placeholder_parser_overrides.empty()) {
         update_apply_status(this->invalidate_step(psGCodeExport));
-		PlaceholderParser &pp = this->placeholder_parser();
-		pp.apply_config(std::move(placeholder_parser_overrides));
+		m_placeholder_parser.apply_config(std::move(placeholder_parser_overrides));
         // Set the profile aliases for the PrintBase::output_filename()
-		pp.set("print_preset",    new_full_config.option("print_settings_id")->clone());
-		pp.set("filament_preset", new_full_config.option("filament_settings_id")->clone());
-		pp.set("printer_preset",  new_full_config.option("printer_settings_id")->clone());
+		m_placeholder_parser.set("print_preset",    new_full_config.option("print_settings_id")->clone());
+		m_placeholder_parser.set("filament_preset", new_full_config.option("filament_settings_id")->clone());
+		m_placeholder_parser.set("printer_preset",  new_full_config.option("printer_settings_id")->clone());
 	    // It is also safe to change m_config now after this->invalidate_state_by_config_options() call.
 	    m_config.apply_only(new_full_config, print_diff, true);
 	    m_config.apply(filament_overrides);
diff --git a/src/libslic3r/PrintBase.hpp b/src/libslic3r/PrintBase.hpp
index b0258fc64..aebc87904 100644
--- a/src/libslic3r/PrintBase.hpp
+++ b/src/libslic3r/PrintBase.hpp
@@ -327,8 +327,6 @@ protected:
 	friend class PrintObjectBase;
     friend class BackgroundSlicingProcess;
 
-    PlaceholderParser&     placeholder_parser() { return m_placeholder_parser; }
-
     tbb::mutex&            state_mutex() const { return m_state_mutex; }
     std::function<void()>  cancel_callback() { return m_cancel_callback; }
 	void				   call_cancel_callback() { m_cancel_callback(); }
@@ -344,6 +342,7 @@ protected:
 
 	Model                                   m_model;
 	DynamicPrintConfig						m_full_print_config;
+    PlaceholderParser                       m_placeholder_parser;
 
 private:
     tbb::atomic<CancelStatus>               m_cancel_status;
@@ -357,8 +356,6 @@ private:
     // The mutex will be used to guard the worker thread against entering a stage
     // while the data influencing the stage is modified.
     mutable tbb::mutex                      m_state_mutex;
-
-    PlaceholderParser                       m_placeholder_parser;
 };
 
 template<typename PrintStepEnum, const size_t COUNT>
diff --git a/src/libslic3r/SLAPrint.cpp b/src/libslic3r/SLAPrint.cpp
index 706053645..2acf688a7 100644
--- a/src/libslic3r/SLAPrint.cpp
+++ b/src/libslic3r/SLAPrint.cpp
@@ -161,7 +161,7 @@ SLAPrint::ApplyStatus SLAPrint::apply(const Model &model, DynamicPrintConfig con
     t_config_option_keys printer_diff  = m_printer_config.diff(config);
     t_config_option_keys material_diff = m_material_config.diff(config);
     t_config_option_keys object_diff   = m_default_object_config.diff(config);
-    t_config_option_keys placeholder_parser_diff = this->placeholder_parser().config_diff(config);
+    t_config_option_keys placeholder_parser_diff = m_placeholder_parser.config_diff(config);
 
     // Do not use the ApplyStatus as we will use the max function when updating apply_status.
     unsigned int apply_status = APPLY_STATUS_UNCHANGED;
@@ -186,12 +186,11 @@ SLAPrint::ApplyStatus SLAPrint::apply(const Model &model, DynamicPrintConfig con
     // only to generate the output file name.
     if (! placeholder_parser_diff.empty()) {
         // update_apply_status(this->invalidate_step(slapsRasterize));
-        PlaceholderParser &pp = this->placeholder_parser();
-        pp.apply_config(config);
+        m_placeholder_parser.apply_config(config);
         // Set the profile aliases for the PrintBase::output_filename()
-        pp.set("print_preset",    config.option("sla_print_settings_id")->clone());
-        pp.set("material_preset", config.option("sla_material_settings_id")->clone());
-        pp.set("printer_preset",  config.option("printer_settings_id")->clone());
+        m_placeholder_parser.set("print_preset",    config.option("sla_print_settings_id")->clone());
+        m_placeholder_parser.set("material_preset", config.option("sla_material_settings_id")->clone());
+        m_placeholder_parser.set("printer_preset",  config.option("printer_settings_id")->clone());
     }
 
     // It is also safe to change m_config now after this->invalidate_state_by_config_options() call.