ember-cli: ember build fails due to conflicting capitalizations

ember build
version: 0.2.7
Could not find watchman, falling back to NodeWatcher for file system events.
Visit http://www.ember-cli.com/#watchman for more info.
Build failed.
Merge error: conflicting capitalizations:
pickadate/lib/translations/fa_IR.js in /my-app/tmp/funnel-dest_Appdgl.tmp
pickadate/lib/translations/fa_ir.js in /my-app/tmp/funnel-dest_Appdgl.tmp
Remove one of the files and re-add it with matching capitalization.
We are strict about this to avoid divergent behavior between case-insensitive Mac/Windows and case-sensitive Linux.
Error: Merge error: conflicting capitalizations:
pickadate/lib/translations/fa_IR.js in /my-app/tmp/funnel-dest_Appdgl.tmp
pickadate/lib/translations/fa_ir.js in /my-app/tmp/funnel-dest_Appdgl.tmp
Remove one of the files and re-add it with matching capitalization.
We are strict about this to avoid divergent behavior between case-insensitive Mac/Windows and case-sensitive Linux.
    at mergeRelativePath (/my-app/node_modules/ember-cli/node_modules/broccoli-merge-trees/index.js:53:21)
    at mergeRelativePath (/my-app/node_modules/ember-cli/node_modules/broccoli-merge-trees/index.js:122:17)
    at mergeRelativePath (/my-app/node_modules/ember-cli/node_modules/broccoli-merge-trees/index.js:122:17)
    at mergeRelativePath (/my-app/node_modules/ember-cli/node_modules/broccoli-merge-trees/index.js:122:17)
    at /my-app/node_modules/ember-cli/node_modules/broccoli-merge-trees/index.js:23:5
    at lib$rsvp$$internal$$tryCatch (/my-app/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:489:16)
    at lib$rsvp$$internal$$invokeCallback (/my-app/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:501:17)
    at lib$rsvp$$internal$$publish (/my-app/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:472:11)
    at lib$rsvp$asap$$flush (/my-app/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:1290:9)
    at process._tickCallback (node.js:355:11)

While pickadate package is listed in my bower.json. I do not import the file pickadate/lib/translations/fa_IR.js in my Brocfile.js.

I’m surprise broccoli is going through this file at all.