Session repeatedly reports "logged out" and stops, burning tokens without completing work; parallel Bash calls race on shared cwd

Environment

• Claude Code CLI
• macOS 26.5 (Darwin 25.5.0)
• Model: Sonnet 5 (claude-sonnet-5)

Issue 1: repeated "logged out" interruptions

During a working session, Claude Code repeatedly reported being logged out
and stopped mid-task, then resumed, then stopped again — several times in
a row. The session never reached a stable state long enough to finish the
in-progress work.

Issue 2: excessive token consumption with no completed work

Correlated with the above: the session consumed a large amount of tokens
while retrying/reconnecting, without making forward progress on the actual
task. Had to exit before anything was completed, with no clear summary of
what (if anything) had been saved.

Issue 3: parallel Bash tool calls race on shared working directory

Separately, in a later session, two Bash tool calls issued in parallel each
ran cd <relative-path> && <command> from the same starting cwd. One
cd apparently succeeded and changed the persistent shell state before the
other's relative path was resolved, so the second call failed with "no such
file or directory" for a directory that provably existed (confirmed
immediately after with pwd/ls from a follow-up call). This suggests
concurrent Bash invocations sharing one persistent shell/cwd are not
isolated from each other.

Impact

Loss of session continuity, wasted tokens, and unreliable relative-path
cd behavior under parallel tool calls.