Nightcore beats don't resume playing correctly after pausing

[bdach]

Type

Game behaviour

Bug description

Reported in https://discord.com/channels/188630481301012481/1097318920991559880/1295680161580056600

With Nightcore mod active, pausing mid-play and unpausing results in nightcore beat samples not being played for some time. They seem to only resume when a "finish" sample is normally supposed to be played (every 16 beats / 4 bars). They also get disabled again for the same number of beats whenever a new timing point is encountered.

Screenshots or videos

https://github.com/user-attachments/assets/b7fcaa25-c8b4-46ca-9419-6892de717593

Version

current master

Logs

n/a

[bdach]

Well if I were to try fix this naively, it would be by essentially reverting https://github.com/ppy/osu/pull/7221/commits/c883c97bab8e81a3bd67db0ef5d4c7110b5d3161...

diff --git a/osu.Game/Rulesets/Mods/ModNightcore.cs b/osu.Game/Rulesets/Mods/ModNightcore.cs
index bb18940f8c..c55ac952ed 100644
--- a/osu.Game/Rulesets/Mods/ModNightcore.cs
+++ b/osu.Game/Rulesets/Mods/ModNightcore.cs
@@ -116,7 +116,7 @@ protected override void OnNewBeat(int beatIndex, TimingControlPoint timingPoint,

                 if (!firstBeat.HasValue || beatIndex < firstBeat)
                     // decide on a good starting beat index if once has not yet been decided.
-                    firstBeat = beatIndex < 0 ? 0 : (beatIndex / segmentLength + 1) * segmentLength;
+                    firstBeat = beatIndex < 0 ? 0 : (beatIndex / segmentLength) * segmentLength;

                 if (beatIndex >= firstBeat)
                     playBeatFor(beatIndex % segmentLength, timingPoint.TimeSignature);

@peppy are you able to provide some insight into that commit? Dec 2019 is already within my range of activity but I don't believe I looked at that original change and there's seemingly not much talk about it on the PR.