tap/difflet/charm error

stacktrace

(node) warning: possible EventEmitter memory leak detected. 11 listeners added. Use emitter.setMaxListeners() to increase limit.
Trace
    at Stream.EventEmitter.addListener (events.js:179:15)
    at Stream.pipe (stream.js:99:8)
    at module.exports .../node_modules/tap/node_modules/difflet/node_modules/charm/index.js:38:15)
    at difflet .../node_modules/tap/node_modules/difflet/index.js:41:17)
    at Function.fn.compare .../node_modules/tap/node_modules/difflet/index.js:20:9)
    at diffObject .../node_modules/tap/lib/tap-assert.js:398:50)
    at assert .../node_modules/tap/lib/tap-assert.js:55:18)
    at Function.equivalent .../node_modules/tap/lib/tap-assert.js:182:12)
    at Test._testAssert .../node_modules/tap/lib/tap-test.js:87:16)
    at Test.<anonymous> .../test/prep/index.js:19:9)
events.js:85
      throw er; // Unhandled 'error' event
            ^
Error: write EPIPE
    at exports._errnoException (util.js:742:11)
    at Object.afterWrite (net.js:766:14)

… this happens when I pipe tap output to tap-bail I'm using node 0.11.13 and the following libs:

├─┬ tap@0.4.12
│ ├── buffer-equal@0.0.1
│ ├── deep-equal@0.0.0
│ ├─┬ difflet@0.2.6
│ │ ├── charm@0.1.2

Any idea where to fix this?