diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index 26ca933f63f..9eb51456396 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -5440,7 +5440,7 @@ double_t GCode::_compute_speed_mm_per_sec(const ExtrusionPath& path, double spee
 
 
 void GCode::cooldown_marker_init() {
-    if (!_cooldown_marker_speed[ExtrusionRole::erExternalPerimeter].empty()) {
+    if (_cooldown_marker_speed[ExtrusionRole::erExternalPerimeter].empty()) {
         std::string allow_speed_change = ";CM_extrude_speed;_EXTRUDE_SET_SPEED";
         //only change speed on external perimeter (and similar) speed if really necessary.
         std::string maybe_allow_speed_change = ";CM_extrude_speed_external;_EXTRUDE_SET_SPEED_MAYBE";
diff --git a/src/libslic3r/GCode/CoolingBuffer.cpp b/src/libslic3r/GCode/CoolingBuffer.cpp
index 07d4e02c467..9445f98ed7c 100644
--- a/src/libslic3r/GCode/CoolingBuffer.cpp
+++ b/src/libslic3r/GCode/CoolingBuffer.cpp
@@ -45,6 +45,7 @@ void CoolingBuffer::reset(const Vec3d &position)
 struct CoolingLine
 {
     enum Type : uint32_t {
+        TYPE_NONE               = 0,
         //first 5 bits are for the extrusiontype (not a flag)
 
         TYPE_SET_TOOL           = 1 << 7,
@@ -79,6 +80,12 @@ struct CoolingLine
         length(0.f), has_move(false), feedrate(0.f), time(0.f), time_max(0.f), slowdown(false) {}
 
     bool adjustable(bool slowdown_external_perimeters) const {
+        std::cout << (this->type & TYPE_ADJUSTABLE) << "=" << (int) this->type << "&" << (int) TYPE_ADJUSTABLE
+                  << " && "
+                  << (slowdown_external_perimeters ||
+                      (!(this->type & TYPE_ADJUSTABLE_MAYBE))) << "="
+                  << slowdown_external_perimeters << "||" << (int) TYPE_ADJUSTABLE_MAYBE
+                  << " && "<<(this->time < this->time_max) << "\n";
         return (this->type & TYPE_ADJUSTABLE) && 
                (slowdown_external_perimeters || (!(this->type & TYPE_ADJUSTABLE_MAYBE))) &&
                this->time < this->time_max;
@@ -401,6 +408,8 @@ std::vector<PerExtruderAdjustments> CoolingBuffer::parse_layer_gcode(const std::
     // Index of an existing CoolingLine of the current adjustment, which holds the feedrate setting command
     // for a sequence of extrusion moves.
     size_t            active_speed_modifier = size_t(-1);
+    // type to add to each next G1 (just for adjustable for now)
+    size_t            current_stamp = CoolingLine::TYPE_NONE;
 
     for (; *line_start != 0; line_start = line_end) 
     {
@@ -460,10 +469,13 @@ std::vector<PerExtruderAdjustments> CoolingBuffer::parse_layer_gcode(const std::
             if (wipe)
                 line.type |= CoolingLine::TYPE_WIPE;
             if (boost::contains(sline, ";_EXTRUDE_SET_SPEED") && ! wipe) {
-                line.type |= CoolingLine::TYPE_ADJUSTABLE;
                 active_speed_modifier = adjustment->lines.size();
-                if (boost::contains(sline, ";_EXTRUDE_SET_SPEED_MAYBE"))
+                line.type |= CoolingLine::TYPE_ADJUSTABLE;
+                current_stamp |= CoolingLine::TYPE_ADJUSTABLE;
+                if (boost::contains(sline, ";_EXTRUDE_SET_SPEED_MAYBE")) {
                     line.type |= CoolingLine::TYPE_ADJUSTABLE_MAYBE;
+                    current_stamp |= CoolingLine::TYPE_ADJUSTABLE_MAYBE;
+                }
             }
             if ((line.type & CoolingLine::TYPE_G92) == 0) {
                 // G0 or G1. Calculate the duration.
@@ -494,6 +506,11 @@ std::vector<PerExtruderAdjustments> CoolingBuffer::parse_layer_gcode(const std::
                     line.length = std::abs(dif[3]);
                 }
                 line.feedrate = new_pos[4];
+                if (line.feedrate > 0.f && line.length > 0.f) {
+                    assert((line.type & CoolingLine::TYPE_ADJUSTABLE) == 0);
+                    assert(active_speed_modifier != size_t(-1));
+                    line.type |= current_stamp;
+                }
                 assert((line.type & CoolingLine::TYPE_ADJUSTABLE) == 0 || line.feedrate > 0.f);
                 if (line.length > 0) {
                     assert(line.feedrate > 0);
@@ -546,6 +563,7 @@ std::vector<PerExtruderAdjustments> CoolingBuffer::parse_layer_gcode(const std::
                 }
             }
             active_speed_modifier = size_t(-1);
+            current_stamp         = CoolingLine::TYPE_NONE;
         } else if (boost::starts_with(sline, ";_TOOLCHANGE")) {
             //not using m_toolchange_prefix anymore because there is no use case for it, there is always a _TOOLCHANGE for when a fan change is needed.
             int prefix = 13;