**Summary**

In the work Begin of the deletion packages API with `timestamps`, when the last requested timestamp is historic, the returned workEnd of the deletion package Begin of the insertiontable, baseline comparison between two past datesEnd of the insertion shows Begin of the insertiontoday'sEnd of the insertion Begin of the deletion today'sEnd of the deletion observed-in versions Begin of the insertioninstead of the versions the work package had at the second date. EveryEnd of the insertion Begin of the deletion while everyEnd of the deletion other Begin of the insertioncolumn,End of the insertion Begin of the deletion attribute,End of the deletion including Begin of the insertionTargetEnd of the insertion Begin of the deletion targetEnd of the deletion versions, Begin of the insertionshows the state atEnd of the insertion Begin of the deletion comes fromEnd of the deletion that Begin of the insertiondate.End of the insertion Begin of the deletion point in time.End of the deletion

**Steps to reproduce**

1. Begin of the insertion A workEnd of the insertion Begin of the deletion WorkEnd of the deletion package Begin of the insertionwhoseEnd of the insertion Begin of the deletion with a journal history in which theEnd of the deletion observed-in versions Begin of the insertionchanged over time,End of the insertion Begin of the deletion changed,End of the deletion for example observed in Begin of the insertion"Baseline 1.0" three days ago, in "Baseline 1.0"End of the insertion Begin of the deletion "1.0" earlierEnd of the deletion and Begin of the insertion"Baseline 1.1" two days ago, andEnd of the insertion in Begin of the insertion"Baseline 1.0", "Baseline 1.1" and "Baseline 1.2" today (target version 1.0, then 1.1, then 1.2 at the same times).

End of the insertion Begin of the deletion "1.1" now.
End of the deletion 2. Begin of the insertion OpenEnd of the insertion Begin of the deletion `GET /api/v3/work_packages/<id>?timestamps=<timestamp beforeEnd of the deletion the Begin of the insertionproject&#x27;s work package tableEnd of the insertion Begin of the deletion change>` (single historic timestamp, no `PT0S`).
3. Compare `_links.observedInVersions` of the elementEnd of the deletion with Begin of the insertionthe columns Target versions and Observed in versions.

3. Baseline, &quot;Between two specific dates&quot;: first date three days ago, second date two days ago (both before today&#x27;s change).


End of the insertion Begin of the deletion `_links.targetVersions`.

End of the deletion **Actual behavior**

Begin of the insertionObserved inEnd of the insertion Begin of the deletion `_links.observedInVersions` lists the currentEnd of the deletion versions Begin of the insertionshows today&#x27;s three values, &quot;Baseline 1.0, Baseline 1.1, ...&quot; with a count of 3, asEnd of the insertion Begin of the deletion ("1.1"). `_links.targetVersions` andEnd of the deletion the Begin of the insertionstate atEnd of the insertion Begin of the deletion other attributes showEnd of the deletion the Begin of the insertionsecond date. TargetEnd of the insertion Begin of the deletion historic state. The `attributesByTimestamp` entry for that timestamp lists the historic observed-inEnd of the deletion versions Begin of the insertionshows &quot;Baseline 1.1&quot; with &quot;Baseline 1.0&quot; struck through, which is the correct state at the second date.End of the insertion Begin of the deletion correctly.End of the deletion

**Expected behavior**

Begin of the insertionObserved in versionsEnd of the insertion Begin of the deletion `_links.observedInVersions` on the elementEnd of the deletion shows the Begin of the deletion observed-inEnd of the deletion versions as of the Begin of the insertionsecond date, &quot;Baseline 1.0, Baseline 1.1&quot;, with the baseline value &quot;Baseline 1.0&quot; struck through, consistent with the TargetEnd of the insertion Begin of the deletion requested timestamp, like targetEnd of the deletion versions Begin of the insertioncolumn.End of the insertion Begin of the deletion do.End of the deletion

**Environment**

dev Begin of the insertionbranch, docker development stack, Chromium.End of the insertion Begin of the deletion branch.End of the deletion

Begin of the insertion**ScreenshotsEnd of the insertion Begin of the deletion **Additional context**

`API::V3::WorkPackages::EagerLoading::HistoricAttributes#override_attributes` copies scalar attributesEnd of the deletion and Begin of the insertionattachments**

baseline-between-dates-observed-in-wrong.png (the bug), baseline-yesterday-ok.png (baseline &quot;since yesterday&quot;, where both columns are correct, for contrast).End of the insertion Begin of the deletion `target_versions` from the historic source (b3e8fc681a2, 2026-08-06) but not `observed_in_versions`, which the historic loader gained later in f9996e159cb (COMMS-977, 2026-09-04). Found while reviewing https://github.com/opf/openproject/pull/25320#discussion_r4337744769. Fix: one more `override_association` call plus a request spec example.End of the deletion