# must fail: adjacency_program_date_time
# adjacency ignores another program date-time (hls::timelines_adjacent)
diff --git a/wai/wai-rs/src/http_binding/hls.rs b/wai/wai-rs/src/http_binding/hls.rs
index 2623644b..e93d4430 100644
--- a/wai/wai-rs/src/http_binding/hls.rs
+++ b/wai/wai-rs/src/http_binding/hls.rs
@@ -412,7 +412,7 @@ pub fn timelines_adjacent(wai: &MediaPlaylist, classical: &MediaPlaylist) -> Res
         if w.extra.discontinuity != c.extra.discontinuity {
             return Err(misaligned(format!("segment {seq}: a discontinuity on one side only")));
         }
-        if w.extra.program_date_time != c.extra.program_date_time {
+        if w.extra.program_date_time.is_some() && c.extra.program_date_time.is_none() {
             return Err(misaligned(format!("segment {seq}: another program date-time")));
         }
         if both_parts && !w.extra.parts.is_empty() && !c.extra.parts.is_empty() && parts_ms(&w.extra.parts) != parts_ms(&c.extra.parts) {