OS Notification broken in sub agents in Claude Code

[vexxvakan]

When I let Claude spawn multiple sub agents to work on tasks in parallel they tend to finish their tasks with an OS notification which in general is what I would expect however this tool call fails:

⏺ Task(Run final checks)
  ⎿mcp-interactive:message_complete_notification (MCP)(projectName: "***", message:
                                                      "Command execution complete. 3/4
                                                      commands successful. One test failure
                                                      detected in abort signal handling.")
   Notification sent. You can now wait for user input.
   +4 more tool uses
  ⎿  Error: Agent 1: Last message was not an assistant message