diff --git a/src/issue.rs b/src/issue.rs
index 25126b1..a193e01 100644
--- a/src/issue.rs
+++ b/src/issue.rs
@@ -133,7 +133,7 @@ pub struct Issue {
     pub original_author: String,
     pub original_author_id: u64,
     pub pin_order: u64,
-    pub pull_request: Option<PullRequestMeta>,
+    pub pull_request: PullRequestMeta,
     #[serde(rename = "ref")]
     pub _ref: String,
     pub repository: RepositoryMeta,
diff --git a/src/repository.rs b/src/repository.rs
index b35e797..c88efff 100644
--- a/src/repository.rs
+++ b/src/repository.rs
@@ -332,8 +332,8 @@ pub struct PrBranchInfo {
 #[derive(serde::Deserialize, Debug, PartialEq)]
 pub struct PullRequestMeta {
     pub merged: bool,
-    #[serde(with = "time::serde::rfc3339")]
-    pub merged_at: time::OffsetDateTime,
+    #[serde(with = "time::serde::rfc3339::option")]
+    pub merged_at: Option<time::OffsetDateTime>,
 }
 
 #[derive(Debug)]