diff --git a/CHANGELOG.md b/CHANGELOG.md
index 348d64aca7ae..f53dec137cbb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -32,6 +32,8 @@ Read our [guidelines for writing a good changelog entry](https://github.com/biom
 
 - Fix [#1172](https://github.com/biomejs/biome/issues/1172). Fix placement of line comment after function expression parentheses, they are now attached to first statement in body. Contributed by @kalleep
 
+- Fix [#1511](https://github.com/biomejs/biome/issues/1511) that made the JavaScript formatter crash. Contributed @Conaclos
+
 ### JavaScript APIs
 
 ### Linter
@@ -1911,7 +1913,7 @@ The following rules are now recommended:
 
   The code action now removes any whitespace between the parameter name and its initialization.
 
-- Relax [noConfusingArrow](https://biomejs.dev/linter/rules/no-confusing-arrow/)
+- Relax `noConfusingArrow`
 
   All arrow functions that enclose its parameter with parenthesis are allowed.
   Thus, the following snippet no longer trigger the rule:
diff --git a/crates/biome_formatter/src/buffer.rs b/crates/biome_formatter/src/buffer.rs
index 420990336ca7..5012067d2c96 100644
--- a/crates/biome_formatter/src/buffer.rs
+++ b/crates/biome_formatter/src/buffer.rs
@@ -557,10 +557,6 @@ fn clean_interned(
                 Some((mut cleaned, rest)) => {
                     let mut is_in_expanded_conditional_content = false;
                     for element in rest {
-                        if is_in_expanded_conditional_content {
-                            continue;
-                        }
-
                         let element = match element {
                             FormatElement::Tag(Tag::StartConditionalContent(condition))
                                 if condition.mode == PrintMode::Expanded =>
diff --git a/crates/biome_js_formatter/tests/specs/ts/issue1511.ts b/crates/biome_js_formatter/tests/specs/ts/issue1511.ts
new file mode 100644
index 000000000000..5ea570eb2e82
--- /dev/null
+++ b/crates/biome_js_formatter/tests/specs/ts/issue1511.ts
@@ -0,0 +1,3 @@
+call(a, function (b: () => t1 | t2) {});
+
+call(a, (b: () => t1 | t2) => {});
diff --git a/crates/biome_js_formatter/tests/specs/ts/issue1511.ts.snap b/crates/biome_js_formatter/tests/specs/ts/issue1511.ts.snap
new file mode 100644
index 000000000000..c39f8cb433b1
--- /dev/null
+++ b/crates/biome_js_formatter/tests/specs/ts/issue1511.ts.snap
@@ -0,0 +1,43 @@
+---
+source: crates/biome_formatter_test/src/snapshot_builder.rs
+info: ts/issue1511.ts
+---
+
+# Input
+
+```ts
+call(a, function (b: () => t1 | t2) {});
+
+call(a, (b: () => t1 | t2) => {});
+
+```
+
+
+=============================
+
+# Outputs
+
+## Output 1
+
+-----
+Indent style: Tab
+Indent width: 2
+Line ending: LF
+Line width: 80
+Quote style: Double Quotes
+JSX quote style: Double Quotes
+Quote properties: As needed
+Trailing comma: All
+Semicolons: Always
+Arrow parentheses: Always
+Bracket spacing: true
+Bracket same line: false
+-----
+
+```ts
+call(a, function (b: () => t1 | t2) {});
+
+call(a, (b: () => t1 | t2) => {});
+```
+
+
diff --git a/website/src/content/docs/internals/changelog.mdx b/website/src/content/docs/internals/changelog.mdx
index 729bddb5ee72..2d33a4098e7a 100644
--- a/website/src/content/docs/internals/changelog.mdx
+++ b/website/src/content/docs/internals/changelog.mdx
@@ -38,6 +38,8 @@ Read our [guidelines for writing a good changelog entry](https://github.com/biom
 
 - Fix [#1172](https://github.com/biomejs/biome/issues/1172). Fix placement of line comment after function expression parentheses, they are now attached to first statement in body. Contributed by @kalleep
 
+- Fix [#1511](https://github.com/biomejs/biome/issues/1511) that made the JavaScript formatter crash. Contributed @Conaclos
+
 ### JavaScript APIs
 
 ### Linter
@@ -1917,7 +1919,7 @@ The following rules are now recommended:
 
   The code action now removes any whitespace between the parameter name and its initialization.
 
-- Relax [noConfusingArrow](https://biomejs.dev/linter/rules/no-confusing-arrow/)
+- Relax `noConfusingArrow`
 
   All arrow functions that enclose its parameter with parenthesis are allowed.
   Thus, the following snippet no longer trigger the rule:
diff --git a/website/src/content/docs/zh-cn/internals/changelog.mdx b/website/src/content/docs/zh-cn/internals/changelog.mdx
index 0eb0fdcdc773..36ce590a7b15 100644
--- a/website/src/content/docs/zh-cn/internals/changelog.mdx
+++ b/website/src/content/docs/zh-cn/internals/changelog.mdx
@@ -1216,7 +1216,7 @@ The following rules are promoted:
 
 #### Removed rules
 
-- Remove [noConfusingArrow](https://biomejs.dev/linter/rules/no-confusing-arrow/).
+- Remove `noConfusingArrow`
 
   Code formatters, such as prettier and Biome, always adds parentheses around the parameter or the body of an arrow function.
   This makes the rule useless.
@@ -1876,7 +1876,7 @@ The following rules are now recommended:
 
   The code action now removes any whitespace between the parameter name and its initialization.
 
-- Relax [noConfusingArrow](https://biomejs.dev/linter/rules/no-confusing-arrow/)
+- Relax `noConfusingArrow`
 
   All arrow functions that enclose its parameter with parenthesis are allowed.
   Thus, the following snippet no longer trigger the rule: