Pipeline error - chmod operation not permitted

[INFO] --- frontend-maven-plugin:1.0:gulp (gulp build) @ pplsreport ---
[INFO] Running 'gulp.js build --no-notification' in /opt/atlassian/bitbucketci/agent/build
[INFO] [09:56:33] Using gulpfile /opt/atlassian/bitbucketci/agent/build/gulpfile.js
[INFO] [09:56:33] Starting 'clean'...
[INFO] [09:56:33] Finished 'clean' after 6.25 ms
[INFO] [09:56:33] Starting 'build'...
[INFO] [09:56:33] Starting 'copy'...
[INFO] [09:56:33] Starting 'inject:vendor'...
[INFO] [09:56:33] Starting 'ngconstant:prod'...
[INFO] [09:56:33] Starting 'languages'...
[INFO] [09:56:33] Finished 'ngconstant:prod' after 155 ms
[INFO] [09:56:33] gulp-inject 1 files into vendor.scss.
[INFO] [09:56:33] gulp-inject 25 files into index.html.
[INFO] [09:56:33] Finished 'languages' after 120 ms
[INFO] [09:56:33] Finished 'inject:vendor' after 235 ms
[INFO] [09:56:34] Finished 'copy' after 385 ms
[INFO] [09:56:34] Starting 'inject:app'...
[INFO] [09:56:34] gulp-inject 115 files into index.html.
[INFO] [09:56:34] 'inject:app' errored after 261 ms
[INFO] [09:56:34] Error: EPERM: operation not permitted, chmod '/opt/atlassian/bitbucketci/agent/build/src/main/webapp/index.html'
[INFO]     at Error (native)
[INFO] [09:56:34] 'build' errored after 649 ms
[INFO] [09:56:34] Error in plugin 'run-sequence(inject:app)'
[INFO] Message:
[INFO]     inject:app stream
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 02:32 min
[INFO] Finished at: 2016-07-23T09:56:34+00:00
[INFO] Final Memory: 46M/487M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal com.github.eirslett:frontend-maven-plugin:1.0:gulp (gulp build) on project pplsreport: Failed to run task: 'gulp.js build --no-notification' failed. (error code 1) -> [Help 1]