diff --git a/fluent-bundle/src/types.ts b/fluent-bundle/src/types.ts
index a78fa9c1..78fb49b5 100644
--- a/fluent-bundle/src/types.ts
+++ b/fluent-bundle/src/types.ts
@@ -108,14 +108,16 @@ export class FluentNumber extends FluentType<number> {
   /**
    * Format this `FluentNumber` to a string.
    */
-  toString(scope: Scope): string {
-    try {
-      const nf = scope.memoizeIntlObject(Intl.NumberFormat, this.opts);
-      return nf.format(this.value);
-    } catch (err) {
-      scope.reportError(err);
-      return this.value.toString(10);
+  toString(scope?: Scope): string {
+    if (scope) {
+      try {
+        const nf = scope.memoizeIntlObject(Intl.NumberFormat, this.opts);
+        return nf.format(this.value);
+      } catch (err) {
+        scope.reportError(err);
+      }
     }
+    return this.value.toString(10);
   }
 }
 
@@ -190,6 +192,10 @@ export class FluentDateTime extends FluentType<number | Date | TemporalObject> {
     this.opts = opts;
   }
 
+  [Symbol.toPrimitive](hint: "number" | "string" | "default"): string | number {
+    return hint === "string" ? this.toString() : this.toNumber();
+  }
+
   /**
    * Convert this `FluentDateTime` to a number.
    * Note that this isn't always possible due to the nature of Temporal objects.
@@ -214,18 +220,20 @@ export class FluentDateTime extends FluentType<number | Date | TemporalObject> {
   /**
    * Format this `FluentDateTime` to a string.
    */
-  toString(scope: Scope): string {
-    try {
-      const dtf = scope.memoizeIntlObject(Intl.DateTimeFormat, this.opts);
-      return dtf.format(
-        this.value as Parameters<Intl.DateTimeFormat["format"]>[0]
-      );
-    } catch (err) {
-      scope.reportError(err);
-      if (typeof this.value === "number" || this.value instanceof Date) {
-        return new Date(this.value).toISOString();
+  toString(scope?: Scope): string {
+    if (scope) {
+      try {
+        const dtf = scope.memoizeIntlObject(Intl.DateTimeFormat, this.opts);
+        return dtf.format(
+          this.value as Parameters<Intl.DateTimeFormat["format"]>[0]
+        );
+      } catch (err) {
+        scope.reportError(err);
       }
-      return this.value.toString();
     }
+    if (typeof this.value === "number" || this.value instanceof Date) {
+      return new Date(this.value).toISOString();
+    }
+    return this.value.toString();
   }
 }
diff --git a/fluent-bundle/test/functions_runtime_test.js b/fluent-bundle/test/functions_runtime_test.js
index 7ed960e4..ddcc26a3 100644
--- a/fluent-bundle/test/functions_runtime_test.js
+++ b/fluent-bundle/test/functions_runtime_test.js
@@ -1,18 +1,17 @@
-import assert from "assert";
 import ftl from "@fluent/dedent";
+import assert from "assert";
 
-import { FluentBundle } from "../esm/bundle.js";
-import { FluentResource } from "../esm/resource.js";
-import { FluentNumber } from "../esm/types.js";
+import {
+  FluentBundle,
+  FluentDateTime,
+  FluentNumber,
+  FluentResource,
+} from "../esm/index.js";
 
 suite("Runtime-specific functions", function () {
-  let bundle, errs;
-
-  setup(function () {
-    errs = [];
-  });
-
   suite("passing into the constructor", function () {
+    let bundle, errs;
+
     suiteSetup(function () {
       bundle = new FluentBundle("en-US", {
         useIsolating: false,
@@ -33,6 +32,7 @@ suite("Runtime-specific functions", function () {
           }
         `)
       );
+      errs = [];
     });
 
     test("works for strings", function () {
@@ -56,4 +56,75 @@ suite("Runtime-specific functions", function () {
       assert.strictEqual(errs.length, 0);
     });
   });
+
+  suite("firefox-devtools/profiler@9c8fb55", () => {
+    /** @type {FluentBundle} */
+    let bundle;
+
+    suiteSetup(() => {
+      const ONE_DAY_IN_MS = 24 * 60 * 60 * 1000;
+      const ONE_YEAR_IN_MS = 365 * ONE_DAY_IN_MS;
+
+      const DATE_FORMATS = {
+        thisDay: { hour: "numeric", minute: "numeric" },
+        thisYear: {
+          month: "short",
+          day: "numeric",
+          hour: "numeric",
+          minute: "numeric",
+        },
+        ancient: {
+          year: "numeric",
+          month: "short",
+          day: "numeric",
+        },
+      };
+
+      const SHORTDATE = args => {
+        const date = args[0];
+        const nowTimestamp = Number(new Date("2025-02-15T12:00"));
+
+        const timeDifference = nowTimestamp - +date;
+        if (timeDifference < 0 || timeDifference > ONE_YEAR_IN_MS) {
+          return new FluentDateTime(date, DATE_FORMATS.ancient);
+        }
+        if (timeDifference > ONE_DAY_IN_MS) {
+          return new FluentDateTime(date, DATE_FORMATS.thisYear);
+        }
+        return new FluentDateTime(date, DATE_FORMATS.thisDay);
+      };
+
+      const messages = ftl`\nkey = { SHORTDATE($date) }\n`;
+      const resource = new FluentResource(messages);
+      bundle = new FluentBundle("en-US", { functions: { SHORTDATE } });
+      bundle.addResource(resource);
+    });
+
+    test("works with difference in hours", function () {
+      const msg = bundle.getMessage("key");
+      const date = new Date("2025-02-15T10:30");
+      const errs = [];
+      const val = bundle.formatPattern(msg.value, { date }, errs);
+      assert.strictEqual(val, "10:30 AM");
+      assert.strictEqual(errs.length, 0);
+    });
+
+    test("works with difference in days", function () {
+      const msg = bundle.getMessage("key");
+      const date = new Date("2025-02-03T10:30");
+      const errs = [];
+      const val = bundle.formatPattern(msg.value, { date }, errs);
+      assert.strictEqual(val, "Feb 3, 10:30 AM");
+      assert.strictEqual(errs.length, 0);
+    });
+
+    test("works with difference in years", function () {
+      const msg = bundle.getMessage("key");
+      const date = new Date("2023-02-03T10:30");
+      const errs = [];
+      const val = bundle.formatPattern(msg.value, { date }, errs);
+      assert.strictEqual(val, "Feb 3, 2023");
+      assert.strictEqual(errs.length, 0);
+    });
+  });
 });
diff --git a/fluent-bundle/test/temporal_test.js b/fluent-bundle/test/temporal_test.js
index 6219b617..2af66a66 100644
--- a/fluent-bundle/test/temporal_test.js
+++ b/fluent-bundle/test/temporal_test.js
@@ -66,7 +66,7 @@ suite("Temporal support", function () {
 
     test("can be converted to a number", function () {
       arg = new FluentDateTime(arg);
-      assert.strictEqual(arg.toNumber(), 0);
+      assert.strictEqual(+arg, 0);
     });
   });
 
@@ -94,7 +94,7 @@ suite("Temporal support", function () {
 
     test("can be converted to a number", function () {
       arg = new FluentDateTime(arg);
-      assert.strictEqual(arg.toNumber(), 0);
+      assert.strictEqual(+arg, 0);
     });
   });
 
@@ -123,7 +123,7 @@ suite("Temporal support", function () {
 
       test("can be converted to a number", function () {
         arg = new FluentDateTime(arg);
-        assert.strictEqual(arg.toNumber(), 0);
+        assert.strictEqual(+arg, 0);
       });
     });
   }
@@ -171,7 +171,7 @@ suite("Temporal support", function () {
 
     test("cannot be converted to a number", function () {
       arg = new FluentDateTime(arg);
-      assert.throws(() => arg.toNumber(), TypeError);
+      assert.throws(() => +arg, TypeError);
     });
   });
 
@@ -203,7 +203,7 @@ suite("Temporal support", function () {
 
     test("cannot be converted to a number", function () {
       arg = new FluentDateTime(arg);
-      assert.throws(() => arg.toNumber(), TypeError);
+      assert.throws(() => +arg, TypeError);
     });
   });
 });