diff --git a/schema.graphql b/schema.graphql
index 9a14750fd..e76349aa9 100644
--- a/schema.graphql
+++ b/schema.graphql
@@ -4865,12 +4865,14 @@ type Commit implements GitObject & Node & Subscribable & UniformResourceLocatabl
     path: String
 
     """
-    Allows specifying a beginning time or date for fetching commits.
+    Allows specifying a beginning time or date for fetching commits. Unexpected
+    results may be returned for dates not between 1970-01-01 and 2099-12-13 (inclusive).
     """
     since: GitTimestamp
 
     """
-    Allows specifying an ending time or date for fetching commits.
+    Allows specifying an ending time or date for fetching commits. Unexpected
+    results may be returned for dates not between 1970-01-01 and 2099-12-13 (inclusive).
     """
     until: GitTimestamp
   ): CommitHistoryConnection!
diff --git a/schema.json b/schema.json
index 63f1e38a6..ef651dbf1 100644
--- a/schema.json
+++ b/schema.json
@@ -12549,7 +12549,7 @@
               },
               {
                 "name": "since",
-                "description": "Allows specifying a beginning time or date for fetching commits.",
+                "description": "Allows specifying a beginning time or date for fetching commits. Unexpected results may be returned for dates not between 1970-01-01 and 2099-12-13 (inclusive).",
                 "type": {
                   "kind": "SCALAR",
                   "name": "GitTimestamp",
@@ -12559,7 +12559,7 @@
               },
               {
                 "name": "until",
-                "description": "Allows specifying an ending time or date for fetching commits.",
+                "description": "Allows specifying an ending time or date for fetching commits. Unexpected results may be returned for dates not between 1970-01-01 and 2099-12-13 (inclusive).",
                 "type": {
                   "kind": "SCALAR",
                   "name": "GitTimestamp",