OpenClaw version: 2026.3.28
OS: macOS 26.3.1 (Apple Silicon)

Description:
When a cron job specifies payload.model (e.g., anthropic/claude-haiku-4-5-20251001), isolated cron sessions ignore it and use the agent's default model instead.

Steps to reproduce:

1. Create a cron job with sessionTarget: "isolated" and payload.model: "anthropic/claude-haiku-4-5-20251001" on an agent whose default model is anthropic/claude-sonnet-4-6
2. Trigger the cron
3. Observe in logs that the session runs on the agent default (Sonnet), not the specified override (Haiku)

Expected behavior: Isolated cron session should use the model specified in payload.model.

Actual behavior: The model override is silently ignored. The session uses the agent's default model.

Workaround: Created a dedicated cron-runner agent with the desired model as its default. This is not sustainable as it requires routing all crons through a single agent.

Notes:

• This worked correctly on 3.13
• The payload.model field is accepted without validation errors — it's silently ignored at runtime
• Affects all isolated cron sessions, not just specific agents