[BUG] match-v5 by-puuid match list frozen at 2025-08-31 for an active TW2 account (returns [] on all routing values)

[ThatWasEasy]

Bug Description
match-v5 by-puuid/{puuid}/ids returns no matches played after 2025-08-31 for a specific TW2 account, even though the account is demonstrably active (summoner revisionDate and champion-mastery lastPlayTime values are current). The account's match-list index appears frozen, on every regional routing value.

Problem Description
For the account ThatWasHard#6079 (TW2), PUUID:

R9tPo_0xNx0nORAdpUtYmDTYc4bniD4WaR_mmaUzBAZKcPwmvC6wuZehgnyk2VQ82eMj2QTG6sVX0Q

• GET https://sea.api.riotgames.com/lol/match/v5/matches/by-puuid/{puuid}/ids?start=0&count=100 (paginated to exhaustion) returns exactly 424 match IDs, ranging from TW2_215735275 (2024-07-19) to TW2_331264690 (2025-08-31). Nothing newer is ever returned.
• The same query with startTime set to any date after 2025-09-01 returns [] on all regional routing values (sea, asia, americas, europe).
• However, the account has been actively playing through July 2026:
  • summoner-v4 (tw2) revisionDate = 1783438587561 (2026-07-07).
  • champion-mastery-v4 (tw2) shows 28 champions with lastPlayTime between 2026-06-24 and 2026-07-07 (matchmade games — mastery points were earned).
• Control test: a current TW2 Challenger player's PUUID (taken from league-v4 challengerleagues) returns up-to-date match IDs (TW2_4287xxxxx) from the sea routing value, so TW2 match ingestion in general is healthy. The problem is specific to this account's match-list index.
• The player's profile on third-party sites (e.g. OP.GG) is likewise stuck at the same date, so this is not client-side.

This looks similar in shape to #1070 (account mapped such that by-puuid match lists come back empty), except here the list is frozen at a point in time rather than empty.

Expected Result
by-puuid/{puuid}/ids returns the account's recent matches (June–July 2026, played on TW2), on the sea routing value like other TW2 accounts.

Actual Result
Only matches up to TW2_331264690 (2025-08-31) are returned. Every query for newer matches returns []:

GET /lol/match/v5/matches/by-puuid/{puuid}/ids?startTime=1748707200&count=100
→ 200 []   (sea, asia, americas, europe)

Developer Impact

• Frequency: 100% of calls for this account.
• Severity: Impossible to build any match-history or playtime feature for the affected account; no workaround exists since the match IDs cannot be discovered through any public endpoint.

Player Impact

• Frequency: Every lookup of this player on any third-party site (OP.GG etc.) shows stale data frozen at 2025-08-31.
• Quantity/Region: At least this one account on TW2; unknown how many accounts share the broken index state.

Preconditions

• Account: ThatWasHard#6079 (TW2), PUUID above.
• Account was inactive between roughly 2025-09 and 2025-11, played sporadically 2025-11–2026-02, and returned to regular play in June 2026.

Repro Steps

1. GET https://asia.api.riotgames.com/riot/account/v1/accounts/by-riot-id/ThatWasHard/6079 → PUUID above; region/by-game/lol confirms tw2.
2. GET https://sea.api.riotgames.com/lol/match/v5/matches/by-puuid/{puuid}/ids?start=0&count=5 → newest ID is TW2_331264690 (gameCreation 2025-08-31).
3. GET https://tw2.api.riotgames.com/lol/champion-mastery/v4/champion-masteries/by-puuid/{puuid} → 28 champions with lastPlayTime ≥ 2026-06-24, e.g. champion 222 at 1783438587000 (2026-07-07).
4. Repeat step 2 with startTime=1756684800 (2025-09-01) on sea, asia, americas, europe → all return [], contradicting step 3.

Issue Comments
If you're also seeing by-puuid match lists frozen at a past date for an active account (particularly on SEA platforms), please add your account's platform, PUUID, and the date the list froze.