Claude Code sub-agents may not wake when their background Bash finishes

Observed repeatedly with many background sub-agents: an agent starts a long test run with Bash run_in_background, ends its turn saying 'waiting for my job', and never resumes, even though the job finished minutes later (lock freed, nothing running, results on disk). The completion notification doesn't reliably restart an idle sub-agent. The lead had to message each one. Working pattern: have sub-agents run long work in the foreground (Bash timeout up to 600000 ms, one case per call), or start it in the background and then poll for a done-marker in the foreground, and never end a turn on 'waiting'. The lead should also periodically compare the agents' claims against ps, lock state and status-file mtimes.