Hey, thanks for reporting this. Looking into your agent session (bc-aa02b6b5-...), the backend confirms it ran on Composer 2 throughout — the model you selected was actually used. The “Codex 5.3 High” shown on the web at cursor.com/agents is a display bug; it doesn’t reflect what model was actually running.
This is a known issue that a few other users have reported as well:
The team is actively working on a fix. For now, the desktop / Glass UI is the reliable source of truth for which model is being used. I’ll close this as a duplicate of the thread above since it’s the same underlying issue — any updates will go there.