diff --git a/src/glean/api_client/models/answerlikes.py b/src/glean/api_client/models/answerlikes.py
index cd1539f0..2c3388e2 100644
--- a/src/glean/api_client/models/answerlikes.py
+++ b/src/glean/api_client/models/answerlikes.py
@@ -3,15 +3,15 @@
 from __future__ import annotations
 from glean.api_client.types import BaseModel
 import pydantic
-from typing import List, TYPE_CHECKING
-from typing_extensions import Annotated, TypedDict
+from typing import List, Optional, TYPE_CHECKING
+from typing_extensions import Annotated, NotRequired, TypedDict
 
 if TYPE_CHECKING:
     from .answerlike import AnswerLike, AnswerLikeTypedDict
 
 
 class AnswerLikesTypedDict(TypedDict):
-    liked_by: List["AnswerLikeTypedDict"]
+    liked_by: NotRequired[Optional[List["AnswerLikeTypedDict"]]]
     liked_by_user: bool
     r"""Whether the user in context liked the answer."""
     num_likes: int
@@ -19,7 +19,9 @@ class AnswerLikesTypedDict(TypedDict):
 
 
 class AnswerLikes(BaseModel):
-    liked_by: Annotated[List["AnswerLike"], pydantic.Field(alias="likedBy")]
+    liked_by: Annotated[
+        Optional[List["AnswerLike"]], pydantic.Field(alias="likedBy")
+    ] = None
 
     liked_by_user: Annotated[bool, pydantic.Field(alias="likedByUser")]
     r"""Whether the user in context liked the answer."""
diff --git a/src/glean/api_client/models/documentcontent.py b/src/glean/api_client/models/documentcontent.py
index 1de9c4df..ce4e92ff 100644
--- a/src/glean/api_client/models/documentcontent.py
+++ b/src/glean/api_client/models/documentcontent.py
@@ -27,7 +27,7 @@ def serialize_model(self, handler):
 
         for n, f in type(self).model_fields.items():
             k = f.alias or n
-            val = serialized.get(k)
+            val = serialized.get(k, serialized.get(n, UNSET_SENTINEL))
 
             if val != UNSET_SENTINEL:
                 if val is not None or k not in optional_fields:
diff --git a/tests/test_model_regressions.py b/tests/test_model_regressions.py
new file mode 100644
index 00000000..7550ac6b
--- /dev/null
+++ b/tests/test_model_regressions.py
@@ -0,0 +1,23 @@
+from glean.api_client import models
+
+
+def test_answer_likes_accepts_null_liked_by():
+    payload = {
+        "likedBy": None,
+        "likedByUser": False,
+        "numLikes": 0,
+    }
+
+    likes = models.AnswerLikes.model_validate(payload)
+
+    assert likes.liked_by is None
+    assert likes.liked_by_user is False
+    assert likes.num_likes == 0
+
+
+def test_document_content_model_dump_keeps_alias_field_value():
+    content = models.DocumentContent(fullTextList=["This is a test document."])
+
+    dumped = content.model_dump()
+
+    assert dumped["fullTextList"] == ["This is a test document."]