diff --git a/src/ytdl_sub/script/script.py b/src/ytdl_sub/script/script.py
index 27b4b1e9..f7c20d88 100644
--- a/src/ytdl_sub/script/script.py
+++ b/src/ytdl_sub/script/script.py
@@ -7,7 +7,8 @@ from typing import Set
 from ytdl_sub.script.functions import Functions
 from ytdl_sub.script.parser import parse
 from ytdl_sub.script.script_output import ScriptOutput
-from ytdl_sub.script.types.resolvable import Lambda, BuiltInFunctionType
+from ytdl_sub.script.types.resolvable import BuiltInFunctionType
+from ytdl_sub.script.types.resolvable import Lambda
 from ytdl_sub.script.types.resolvable import Resolvable
 from ytdl_sub.script.types.syntax_tree import SyntaxTree
 from ytdl_sub.script.types.variable import FunctionArgument
@@ -142,6 +143,24 @@ class Script:
                     f"{nested_custom_function.num_input_args}"
                 )
 
+    def _get_lambda_function_names_to_evaluate(self, function: BuiltInFunctionType) -> Set[str]:
+        lambda_function_names: Set[str] = set()
+        for lamb in SyntaxTree(function.args).lambdas:
+            if lamb in function.args:
+                lambda_function_names.add(lamb.value)
+
+            # See if the arg outputs a lambda (from an if).
+            # If so, add the possible lambda to be checked
+            for arg in function.args:
+                if (
+                    isinstance(arg, BuiltInFunctionType)
+                    and arg.output_type() == Lambda
+                    and lamb in arg.args
+                ):
+                    lambda_function_names.add(lamb.value)
+
+        return lambda_function_names
+
     def _ensure_lambda_usage_num_input_arguments_valid(
         self, prefix: str, name: str, definition: SyntaxTree
     ):
@@ -157,16 +176,7 @@ class Script:
             if not (lambda_type := spec.is_lambda_like):
                 return
 
-            lambda_function_names: Set[str] = set()
-            for lamb in SyntaxTree(function.args).lambdas:
-                if lamb in function.args:
-                    lambda_function_names.add(lamb.value)
-
-                # See if the arg outputs a lambda (from an if).
-                # If so, add the possible lambda to be checked
-                for arg in function.args:
-                    if isinstance(arg, BuiltInFunctionType) and arg.output_type() == Lambda and lamb in arg.args:
-                        lambda_function_names.add(lamb.value)
+            lambda_function_names = self._get_lambda_function_names_to_evaluate(function=function)
 
             # Only case len(lambda_function_names) > 1 is when used in if-statements
             for lambda_function_name in lambda_function_names:
diff --git a/src/ytdl_sub/script/types/variable_dependency.py b/src/ytdl_sub/script/types/variable_dependency.py
index ec7be6d5..eb5f646e 100644
--- a/src/ytdl_sub/script/types/variable_dependency.py
+++ b/src/ytdl_sub/script/types/variable_dependency.py
@@ -43,7 +43,7 @@ class VariableDependency(ABC):
                 output.append(arg)
             elif instance and isinstance(arg, ttype):
                 output.append(arg)
-            elif type(arg) == ttype:
+            elif type(arg) == ttype:  # pylint: disable=unidiomatic-typecheck
                 output.append(arg)
 
             if isinstance(arg, VariableDependency):
diff --git a/src/ytdl_sub/script/utils/type_checking.py b/src/ytdl_sub/script/utils/type_checking.py
index 856e75e4..2489760b 100644
--- a/src/ytdl_sub/script/utils/type_checking.py
+++ b/src/ytdl_sub/script/utils/type_checking.py
@@ -53,6 +53,25 @@ def get_optional_type(optional_type: Type) -> Type[NamedType]:
     return [arg for arg in optional_type.__args__ if arg != type(None)][0]
 
 
+def _is_union_compatible(
+    arg_type: Type[NamedType],
+    expected_union_type: Type[Resolvable | Optional[Resolvable]],
+) -> bool:
+    if issubclass(arg_type, (NamedCustomFunction, Variable)):
+        return True  # custom-function/variable can be anything, so pass for now
+
+    # if the input arg is a union, do a direct comparison
+    if is_union(arg_type):
+        return arg_type == expected_union_type
+
+    # otherwise, iterate the union to see if it's compatible
+    for union_type in expected_union_type.__args__:
+        if issubclass(arg_type, union_type):
+            return True
+
+    return False
+
+
 def _is_type_compatible(
     arg_type: Type[NamedType],
     expected_arg_type: Type[Resolvable | Optional[Resolvable]],
@@ -63,22 +82,11 @@ def _is_type_compatible(
     True if arg is compatible with expected_arg_type. False otherwise.
     """
     if is_union(expected_arg_type):
-        if issubclass(arg_type, (NamedCustomFunction, Variable)):
-            return True  # custom-function/variable can be anything, so pass for now
+        return _is_union_compatible(arg_type=arg_type, expected_union_type=expected_arg_type)
 
-        # if the input arg is a union, do a direct comparison
-        if is_union(arg_type):
-            return arg_type == expected_arg_type
-
-        # otherwise, iterate the union to see if it's compatible
-        for union_type in expected_arg_type.__args__:
-            if issubclass(arg_type, union_type):
-                return True
-
-        return False
     # If the input is a union and the expected type is not, see if
     # each possible union input is compatible with the expected type
-    elif is_union(arg_type):
+    if is_union(arg_type):
         for union_type in arg_type.__args__:
             if not _is_type_compatible(union_type, expected_arg_type):
                 return False
diff --git a/tests/unit/script/functions/test_conditional_functions.py b/tests/unit/script/functions/test_conditional_functions.py
index 5cf04a18..eff73214 100644
--- a/tests/unit/script/functions/test_conditional_functions.py
+++ b/tests/unit/script/functions/test_conditional_functions.py
@@ -101,3 +101,37 @@ class TestConditionalFunction:
                 )
             }"""
             )
+
+    @pytest.mark.parametrize(
+        "function_str, expected_output",
+        [
+            ("{%if(True, True, %assert(False, 'should not reach'))}", True),
+            ("{%if(False, %assert(False, 'should not reach'), False)}", False),
+        ],
+    )
+    def test_if_function_only_evaluates_branch(self, function_str: str, expected_output: bool):
+        output = single_variable_output(function_str)
+        assert output == expected_output
+
+    @pytest.mark.parametrize(
+        "function_str, expected_output",
+        [
+            ("{%elif(True, True, %assert(False, 'should not reach'))}", True),
+            ("{%elif(False, %assert(False, 'should not reach'), False)}", False),
+        ],
+    )
+    def test_elif_function_only_evaluates_branch(self, function_str: str, expected_output: bool):
+        output = single_variable_output(function_str)
+        assert output == expected_output
+
+    @pytest.mark.parametrize(
+        "function_str, expected_output",
+        [
+            ("{%if_passthrough(True, %assert(False, 'should not reach'))}", True),
+        ],
+    )
+    def test_if_passthrough_function_only_evaluates_branch(
+        self, function_str: str, expected_output: bool
+    ):
+        output = single_variable_output(function_str)
+        assert output == expected_output