[Bug]: English timestamped messages produce Chinese/German profile output #402

Area

src/everos

What happened?

I ingested a single conversation consisting entirely of English, timestamped messages between two users. Episode output is generated in English, but profile generation is not. One user’s profile is almost entirely Chinese; the other begins in English and then switches largely to German. No non-English source text was provided.

Steps to reproduce

1. Ingest a conversation consisting entirely of English messages between two users via /api/v2/memory/add.
2. Give each message an explicit Unix-millisecond timestamp and keep all messages in the same session.
3. Call /api/v2/memory/flush for the session.
4. Retrieve each user’s profile with /api/v2/memory/get using memory_type: "profile".
5. Observe that the source messages and generated episodes are English, but the generated profile content is not consistently English.
6. In my current reproduction, first user's profile is generated almost entirely in Chinese, while second user's profile starts in English and then switches to German.
7. Re-seeding under a fresh user/session namespace reproduces the problem; an earlier run produced German profile output from the same kind of English-only input.

Environment

macos
python 3.12.13

Logs or screenshots

PROFILE summary: Colin是素食者,不吃肉类,例如火鸡。
 [ei_6a764df6d12c94701ca5774e] explicit_info / 饮食偏好
 description: Colin是素食者,不吃肉类,例如火鸡。
 evidence: Colin提醒Kathryn自己是素食者,不要让他误点含火鸡肉的食物。
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colin-v3 / episode
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EPISODE 6a764e1fd12c94701ca57774 score=None chars=711 facts=0
On July 28, 2026 (Tuesday), Colin told Kathryn that the dentist had called and said he wanted a bagel. Kathryn replied that they literally have bagels. 
 [ei_6a764e27d12c94701ca57779] explicit_info / anniversary preference
 description: Kathryn bevorzugt kleine, einfache Feiern zum Jahrestag statt teurer oder aufwendiger Veranstaltungen.
 evidence: Am 2026年07月27日 um 03:53:00 sagte sie explizit: 'Something small. I don't want a giant expensive dinner.'