diff --git a/crates/script/src/tests/ease_presets.rs b/crates/script/src/tests/ease_presets.rs
index 009cc59c6..f075250b2 100644
--- a/crates/script/src/tests/ease_presets.rs
+++ b/crates/script/src/tests/ease_presets.rs
@@ -608,3 +608,37 @@ fn presets_saved_by_the_old_core_panel_carry_over() {
     let win = open_panel(&mut s);
     assert_eq!(control(&mut s, win, "presets")["items"].as_array().unwrap().len(), 12);
 }
+
+/// #2465: the Linear preset sets Linear interpolation on every side it applies to, including the
+/// unused first-in and last-out sides; editing its speeds makes a Bezier curve.
+#[test]
+fn the_linear_preset_sets_linear_interpolation_and_edited_speeds_give_bezier() {
+    let store = Arc::new(MemoryConfig::default());
+    let mut s = session(&store);
+    let l = setup(&mut s);
+    animate(&mut s, l, "transform/opacity", &[(0.0, json!(0)), (1.0, json!(100)), (3.0, json!(20))]);
+    s.execute("prop.select", json!({"layer": l, "path": "transform/opacity"})).unwrap();
+    let win = open_panel(&mut s);
+    // Start from Bezier keys so Linear has something to restore.
+    ok(
+        &mut s,
+        r#"var p = app.project.activeItem.layer(1).transform.opacity, K = KeyframeInterpolationType;
+        for (var i = 1; i <= p.numKeys; i++) p.setInterpolationTypeAtKey(i, K.BEZIER, K.BEZIER);"#,
+    );
+    let op = prop(&s, l, "transform/opacity");
+    for (i, k) in op.keys.iter().enumerate() {
+        assert_eq!((k.in_interp, k.out_interp), (Interp::Bezier, Interp::Bezier), "initial key {i}");
+    }
+    let steps = s.history.undo.len();
+    set(&mut s, win, "presets", json!("Linear"));
+    assert_eq!(s.history.undo.len(), steps + 1, "one undo step");
+    let op = prop(&s, l, "transform/opacity");
+    for (i, k) in op.keys.iter().enumerate() {
+        assert_eq!((k.in_interp, k.out_interp), (Interp::Linear, Interp::Linear), "key {i}");
+    }
+    // Edited speeds make a custom Bezier curve even though Linear is still the selected preset.
+    select_keys(&mut s, l, &[("transform/opacity", 1.0)]);
+    apply_typed(&mut s, win, "In-Out", [33.0, 2.0, 33.0, 2.0]);
+    let k = &prop(&s, l, "transform/opacity").keys[1];
+    assert_eq!((k.in_interp, k.out_interp), (Interp::Bezier, Interp::Bezier));
+}
diff --git a/extensions/scriptui-panels/Ease Presets.jsx b/extensions/scriptui-panels/Ease Presets.jsx
index 6f6eadae5..9f4ea2185 100644
--- a/extensions/scriptui-panels/Ease Presets.jsx	
+++ b/extensions/scriptui-panels/Ease Presets.jsx	
@@ -18,6 +18,8 @@
 // segment on that side. So a selected pair gets the whole curve, and a single key works too.
 // Roving keys are skipped: they pass speed straight through (their sides stay linear), so an ease
 // set on them wouldn't play.
+// The built-in Linear preset uses Linear interpolation, including on unused endpoint sides
+// so a fully linear key has a diamond icon; the other presets use Bezier.
 //
 // User presets are kept with app.settings (section "Ease Presets", key "userPresets") as JSON:
 // {"version": 1, "presets": [{"name": …, "curve": {"outInfluence", "outSpeed", "inInfluence",
@@ -29,6 +31,7 @@
   var MAX_NAME = 64;
   var MIN_INFLUENCE = 0.1;
   var MAX_SPEED = 100;
+  var LINEAR = KeyframeInterpolationType.LINEAR;
   var BEZIER = KeyframeInterpolationType.BEZIER;
   var HOLD = KeyframeInterpolationType.HOLD;
 
@@ -178,16 +181,16 @@
 
   // Ease one side of key `k` with `eases`, leaving its other side as it plays (auto-Bezier and
   // linear sides keep their shape; a continuous key stops being continuous, its sides now differ).
-  function easeSide(p, k, out, eases) {
+  function easeSide(p, k, out, eases, interpolation) {
     var inType = p.keyInInterpolationType(k), outType = p.keyOutInterpolationType(k);
     var inEase = p.keyInTemporalEase(k), outEase = p.keyOutTemporalEase(k);
     if (p.keyTemporalContinuous(k)) p.setTemporalContinuousAtKey(k, false);
     if (out) {
       p.setTemporalEaseAtKey(k, inEase, eases);
-      p.setInterpolationTypeAtKey(k, inType, BEZIER);
+      p.setInterpolationTypeAtKey(k, inType, interpolation);
     } else {
       p.setTemporalEaseAtKey(k, eases, outEase);
-      p.setInterpolationTypeAtKey(k, BEZIER, outType);
+      p.setInterpolationTypeAtKey(k, interpolation, outType);
     }
   }
 
@@ -201,7 +204,7 @@
   // Ease the sides `mode` names ("In", "Out" or "In-Out") of every selected keyframe with `c`, in
   // one undo step: a side with a neighbouring key, scaled to the segment on that side. Returns
   // {eased, roving}: the number of keyframes eased, and of selected roving keyframes skipped.
-  function applyCurve(c, mode) {
+  function applyCurve(c, mode, interpolation) {
     var keyed = selectedKeyed(), sides = [], keys = 0, roving = 0;
     var doIn = mode !== "Out", doOut = mode !== "In";
     // Every side and its eases first: the segments are measured before any key changes.
@@ -214,16 +217,16 @@
           continue;
         }
         var s = doIn && k > 1 ? slopes(p, k - 1) : null;
-        if (s) sides.push({ prop: p, key: k, out: false, eases: eases(s, c.inSpeed, c.inInfluence) });
+        if (s || (doIn && interpolation === LINEAR)) sides.push({ prop: p, key: k, out: false, eases: s ? eases(s, c.inSpeed, c.inInfluence) : p.keyInTemporalEase(k) });
         s = doOut && k < p.numKeys ? slopes(p, k) : null;
-        if (s) sides.push({ prop: p, key: k, out: true, eases: eases(s, c.outSpeed, c.outInfluence) });
+        if (s || (doOut && interpolation === LINEAR)) sides.push({ prop: p, key: k, out: true, eases: s ? eases(s, c.outSpeed, c.outInfluence) : p.keyOutTemporalEase(k) });
         if (sides.length > before) keys++;
       }
     }
     if (!sides.length) return { eased: 0, roving: roving };
     app.beginUndoGroup("Apply Ease Preset");
     try {
-      for (var e = 0; e < sides.length; e++) easeSide(sides[e].prop, sides[e].key, sides[e].out, sides[e].eases);
+      for (var e = 0; e < sides.length; e++) easeSide(sides[e].prop, sides[e].key, sides[e].out, sides[e].eases, interpolation);
     } finally {
       app.endUndoGroup();
     }
@@ -384,7 +387,10 @@
 
   function apply(c, what) {
     var m = mode.selection ? mode.selection.text : "In-Out";
-    var r = applyCurve(c, m), n = r.eased;
+    // Linear is an interpolation type too, so its keys get diamond icons. Edited speeds
+    // make a custom Bezier curve even while Linear remains selected in the list.
+    var interpolation = list.selection && list.selection.text === "Linear" && c.outSpeed === 1 && c.inSpeed === 1 ? LINEAR : BEZIER;
+    var r = applyCurve(c, m, interpolation), n = r.eased;
     var side = m === "In" ? "before it" : m === "Out" ? "after it" : "next to it";
     var skipped = r.roving > 0 ? "skipped " + r.roving + " roving keyframe(s); turn off Roving to ease them" : "";
     if (n > 0) status.text = "Eased " + n + " keyframe(s) (" + m + ") with " + what + (skipped ? "; " + skipped : "");