5.5.0 can fail on Mac after extended period, epmd not restarting with Couchbase, machine reboot fixes issue

I've been running 5.5.0 on a research laptop since it was released.

This morning the laptop displayed the message shown in the attached screenshot:    

    Problem Running Couchbase

    Couchbase Server doesn't seem to be operating properly. Check Console logs for more details.

The babysitter log contains a number of crash report messages at the end, e.g.:

[error_logger:error,2018-10-14T17:38:45.571-07:00,babysitter_of_ns_1@127.0.0.1:error_logger<0.6.0>:ale_error_logger_handler:do_log:203]

=========================CRASH REPORT=========================

  crasher:

    initial call: ale_dynamic_sup:delay_death_init/3

    pid: <0.783.87>

    registered_name: []

    exception exit: {stderr_port_died,epipe}

      in function  ale_dynamic_sup:handle_child_exit/4 (src/ale_dynamic_sup.erl, line 118)

    ancestors: [ale_dynamic_sup,ale_sup,<0.39.0>]

    messages: []

    links: [<0.41.0>]

    dictionary: []

    trap_exit: true

    status: running

    heap_size: 376

    stack_size: 27

    reductions: 133

  neighbours:

Full cbcollect can be found here: http://research.corp.couchbase.com/research.zip

I have tried restarting Couchbase Server but it won't come up.