Fix tracker start date being shifted by the UTC offset (#4049)

Closes #1340
Closes #4049

CHANGELOG.md

@@ -40,6 +40,7 @@ The format is a modified version of [Keep a Changelog](https://keepachangelog.co
 - Fixed updating from v0.20.x failing when the database had duplicate history or tracking entries, or damaged indexes ([@AntsyLich](https://github.com/AntsyLich))
 - Fixed a crash when a back gesture was still in progress as the reader or a dialog closed ([@AntsyLich](https://github.com/AntsyLich))
 - Fixed Kitsu login and other requests that send data failing with "Failed to bypass Cloudflare" ([@AntsyLich](https://github.com/AntsyLich))
+- Fixed tracker start date being off by a day when adding tracking to an entry with read history in some timezones ([@hazptr](https://github.com/hazptr)) ([#4049](https://github.com/mihonapp/mihon/pull/4049))
 
 ## [v0.21.1] - 2026-10-12
 ### Fixed

app/src/main/java/eu/kanade/domain/track/interactor/AddTracks.kt

@@ -8,10 +8,8 @@ import eu.kanade.tachiyomi.data.track.EnhancedTracker
 import eu.kanade.tachiyomi.data.track.Tracker
 import eu.kanade.tachiyomi.data.track.TrackerManager
 import eu.kanade.tachiyomi.source.Source
-import eu.kanade.tachiyomi.util.lang.convertEpochMillisZone
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
-import kotlinx.datetime.TimeZone
 import logcat.LogPriority
 import tachiyomi.core.common.util.system.logcat
 import tachiyomi.domain.chapter.interactor.GetChaptersByMangaId
@@ -61,10 +59,7 @@ class AddTracks(
                     .minOrNull()
 
                 firstReadChapterDate?.let {
-                    val startDate = firstReadChapterDate.toEpochMilliseconds().convertEpochMillisZone(
-                        TimeZone.currentSystemDefault(),
-                        TimeZone.UTC,
-                    )
+                    val startDate = firstReadChapterDate.toEpochMilliseconds()
                     track = track.copy(
                         startDate = Instant.fromEpochMilliseconds(startDate),
                     )