diff --git a/catalog/rest/scan_task_decoder.go b/catalog/rest/scan_task_decoder.go
index 680351b61..70a056512 100644
--- a/catalog/rest/scan_task_decoder.go
+++ b/catalog/rest/scan_task_decoder.go
@@ -343,6 +343,9 @@ func decodeRESTDeleteFile(
 		if len(wire.EqualityIDs) != 0 {
 			return nil, errors.New("position-deletes file must not carry equality-ids")
 		}
+		if format != iceberg.PuffinFile && (wire.ContentOffset != nil || wire.ContentSizeInBytes != nil) {
+			return nil, errors.New("content-offset and content-size-in-bytes are only valid for Puffin deletion vectors")
+		}
 		if wire.ContentOffset != nil {
 			if *wire.ContentOffset < 0 {
 				return nil, fmt.Errorf("content-offset must be non-negative: %d", *wire.ContentOffset)
diff --git a/catalog/rest/scan_task_decoder_test.go b/catalog/rest/scan_task_decoder_test.go
index 0b0c82d1a..62be12841 100644
--- a/catalog/rest/scan_task_decoder_test.go
+++ b/catalog/rest/scan_task_decoder_test.go
@@ -390,6 +390,28 @@ func TestDecodeScanTasksRejectsMalformedPayloads(t *testing.T) {
 			},
 			want: "must not carry equality-ids",
 		},
+		{
+			name: "non-Puffin position delete with content offset",
+			mutate: func(w *ScanTasks) {
+				w.DeleteFiles[0].ContentOffset = int64Ptr(10)
+			},
+			want: "only valid for Puffin deletion vectors",
+		},
+		{
+			name: "non-Puffin position delete with content size",
+			mutate: func(w *ScanTasks) {
+				w.DeleteFiles[0].ContentSizeInBytes = int64Ptr(20)
+			},
+			want: "only valid for Puffin deletion vectors",
+		},
+		{
+			name: "non-Puffin position delete with blob range",
+			mutate: func(w *ScanTasks) {
+				w.DeleteFiles[0].ContentOffset = int64Ptr(10)
+				w.DeleteFiles[0].ContentSizeInBytes = int64Ptr(20)
+			},
+			want: "only valid for Puffin deletion vectors",
+		},
 		{
 			name: "puffin missing blob range",
 			mutate: func(w *ScanTasks) {