Hey, thanks for the report and the clear steps. This is a known regression. The explore subagent set via the UI with Fast turned off still resolves to Composer 2.5 Fast. I can reproduce it, and we’re tracking it on our side, but I don’t have an ETA yet.
Related threads for context:
- Sub-agent model being ignored and premium models being erroniously used for subagents
- Let us disable composer-2-fast, it's 3x the price and forced on subagents
Once there’s an update on the fix, I’ll post it here.