Hey, this is a known issue caused by a diff rendering bug. When diffs don’t render correctly, the Revert, Undo, and Save buttons can disappear too.
For now, the safest workaround is to make a git commit before each agent session. That way you can always roll back with git checkout -- . or git stash if the Revert button is missing.
Related thread with more context: Keep / Undo buttons missing and “Discard to checkpoint” not reverting changes (auto-applies edits).