fix: consistently apply playout offset when generating xmltv (#2863)

CHANGELOG.md

@@ -11,6 +11,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Fixed
 - Fix `Add Playout` button not opening drop down menu (regression from v26.4.0)
+- Consistently apply playout offset when generating XMLTV
 
 ## [26.4.0] - 2026-04-18
 ### Changed

ErsatzTV.Application/Channels/Commands/RefreshChannelDataHandler.cs

@@ -215,6 +215,18 @@ public class RefreshChannelDataHandler : IRequestHandler<RefreshChannelData>
                 .AsSplitQuery()
                 .ToListAsync(cancellationToken);
 
+            // apply playout offset to all items consistently
+            foreach (Playout playout in playouts)
+            {
+                foreach (PlayoutItem item in playout.Items)
+                {
+                    item.Start += playoutOffset;
+                    item.GuideStart += playoutOffset;
+                    item.Finish += playoutOffset;
+                    item.GuideFinish += playoutOffset;
+                }
+            }
+
             await using RecyclableMemoryStream ms = _recyclableMemoryStreamManager.GetStream();
             await using var xml = XmlWriter.Create(
                 ms,
@@ -238,11 +250,6 @@ public class RefreshChannelDataHandler : IRequestHandler<RefreshChannelData>
                             .OrderBy(pi => pi.Start)
                             .Filter(pi => pi.StartOffset <= finish)
                             .ToList();
-                        foreach (var item in floodSorted)
-                        {
-                            item.Start += playoutOffset;
-                            item.Finish += playoutOffset;
-                        }
 
                         await WritePlayoutXml(
                             request,
@@ -264,11 +271,6 @@ public class RefreshChannelDataHandler : IRequestHandler<RefreshChannelData>
                             .OrderBy(pi => pi.Start)
                             .Filter(pi => pi.StartOffset <= finish)
                             .ToList();
-                        foreach (var item in blockSorted)
-                        {
-                            item.Start += playoutOffset;
-                            item.Finish += playoutOffset;
-                        }
 
                         await WriteBlockPlayoutXml(
                             request,
@@ -288,11 +290,6 @@ public class RefreshChannelDataHandler : IRequestHandler<RefreshChannelData>
                         var externalJsonSorted = (await CollectExternalJsonItems(playout.ScheduleFile))
                             .Filter(pi => pi.StartOffset <= finish)
                             .ToList();
-                        foreach (var item in externalJsonSorted)
-                        {
-                            item.Start += playoutOffset;
-                            item.Finish += playoutOffset;
-                        }
 
                         await WritePlayoutXml(
                             request,