diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 537845cada7..fbf2d34eef9 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -5433,6 +5433,14 @@ StartupXLOG(void)
 	 */
 	if (!XLogRecPtrIsInvalid(missingContrecPtr))
 	{
+		/*
+		 * We should only have a missingContrecPtr if we're not switching to
+		 * a new timeline. When a timeline switch occurs, WAL is copied from
+		 * the old timeline to the new only up to the end of the last complete
+		 * record, so there can't be an incomplete WAL record that we need to
+		 * disregard.
+		 */
+		Assert(newTLI == endOfRecoveryInfo->lastRecTLI);
 		Assert(!XLogRecPtrIsInvalid(abortedRecPtr));
 		EndOfLog = missingContrecPtr;
 	}
diff --git a/src/backend/access/transam/xlogrecovery.c b/src/backend/access/transam/xlogrecovery.c
index a59a0e826bb..4ad145dd167 100644
--- a/src/backend/access/transam/xlogrecovery.c
+++ b/src/backend/access/transam/xlogrecovery.c
@@ -3024,12 +3024,18 @@ ReadRecord(XLogPrefetcher *xlogprefetcher, int emode,
 		if (record == NULL)
 		{
 			/*
-			 * When not in standby mode we find that WAL ends in an incomplete
-			 * record, keep track of that record.  After recovery is done,
-			 * we'll write a record to indicate to downstream WAL readers that
-			 * that portion is to be ignored.
+			 * When we find that WAL ends in an incomplete record, keep track
+			 * of that record.  After recovery is done, we'll write a record to
+			 * indicate to downstream WAL readers that that portion is to be
+			 * ignored.
+			 *
+			 * However, when ArchiveRecoveryRequested = true, we're going to
+			 * switch to a new timeline at the end of recovery. We will only
+			 * copy WAL over to the new timeline up to the end of the last
+			 * complete record, so if we did this, we would later create an
+			 * overwrite contrecord in the wrong place, breaking everything.
 			 */
-			if (!StandbyMode &&
+			if (!ArchiveRecoveryRequested &&
 				!XLogRecPtrIsInvalid(xlogreader->abortedRecPtr))
 			{
 				abortedRecPtr = xlogreader->abortedRecPtr;