Compaction happens at low context usage (e.g. 20%) and don't get reported as an actual checkpoint?

Describe the bug

I keep seeing gpt-5.6 sol getting compacted at like 20% context usage. It shows a message like this and if I run /session checkpoints like it says in the message it says no checkpoints. Well, which is it, did you just add a checkpoint to the session or not?

Affected version

1.0.81

Steps to reproduce the behavior

1. Use GPT-5.6 Sol for awhile and see it auto-decide to compact
2. See the session compact message
3. Type /session checkpoints

Expected behavior

What's the point of having 80% available context when you force compaction at 20%.
I also expect that if you do a compaction it shows up in the list instead of this gaslighting message about there being a checkpoint and then doing the exact recommended command shows nothing.

Additional context

Windows Terminal on x64 win11

Commencez par reproduire le comportement avec GPT-5.6 Sol : observez le message de compactage automatique, puis exécutez /session checkpoints comme indiqué. Suivez les points d’entrée du compactage et de la génération des rapports de checkpoints, et considérez l’issue comme terminée lorsque le seuil de compactage et le message sont cohérents et que le checkpoint résultant apparaît dans la liste.