Composer hangs at @php artisan package:discover --ansi

Question

I recently did a deploy to Laravel forge and my power went out. When it came back, the deploy failed, and is just hanging on

@php artisan package:discover --ansi

and it just exist with the following error:

Script @php artisan package:discover --ansi handling the post-autoload-dump event returned with error code 137

There are no entries in my laravel logs. What I've tried:

1. I've logged into the server and done a manual composer install, but same effect.
2. I've manually deleted the vendor directory and composer.lock and tried a composer install but it had not effect.
3. I've deleted files in bootstrap/cache/* and run composer dump but that didn't work either.

Does anyone know what I can do to fix this? All my deploys are now failing and I can't get my server back up.