Old image uploads become broken images

I have a similar problem (I think) after an update to stable v1.8.7, but the command rake uploads:recover_from_tombstone says:

  1 / 9 ( 11.1%)
Restoring /var/www/discourse/public/uploads/tombstone/default/original/1X/27bf77d1d3f09d13b1f89cf97552a8ae19aa4d98.png...rake aborted!
TypeError: no implicit conversion of Symbol into Integer
/var/www/discourse/lib/upload_creator.rb:190:in `[]'
/var/www/discourse/lib/upload_creator.rb:190:in `should_crop?'
/var/www/discourse/lib/upload_creator.rb:47:in `block in create_for'
/var/www/discourse/lib/distributed_mutex.rb:21:in `synchronize'
/var/www/discourse/lib/distributed_mutex.rb:5:in `synchronize'
/var/www/discourse/lib/upload_creator.rb:34:in `create_for'
/var/www/discourse/lib/tasks/uploads.rake:441:in `block (4 levels) in recover_from_tombstone'
/var/www/discourse/lib/tasks/uploads.rake:440:in `open'
/var/www/discourse/lib/tasks/uploads.rake:440:in `block (3 levels) in recover_from_tombstone'
/var/www/discourse/vendor/bundle/ruby/2.3.0/gems/nokogiri-1.7.2/lib/nokogiri/xml/node_set.rb:187:in `block in each'
/var/www/discourse/vendor/bundle/ruby/2.3.0/gems/nokogiri-1.7.2/lib/nokogiri/xml/node_set.rb:186:in `upto'
/var/www/discourse/vendor/bundle/ruby/2.3.0/gems/nokogiri-1.7.2/lib/nokogiri/xml/node_set.rb:186:in `each'
/var/www/discourse/lib/tasks/uploads.rake:428:in `block (2 levels) in recover_from_tombstone'
/var/www/discourse/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.8/lib/active_record/relation/delegation.rb:46:in `each'
/var/www/discourse/vendor/bundle/ruby/2.3.0/gems/activerecord-4.2.8/lib/active_record/relation/delegation.rb:46:in `each'
/var/www/discourse/lib/tasks/uploads.rake:424:in `block in recover_from_tombstone'
/var/www/discourse/lib/tasks/uploads.rake:420:in `each'
/var/www/discourse/lib/tasks/uploads.rake:420:in `each_with_index'
/var/www/discourse/lib/tasks/uploads.rake:420:in `recover_from_tombstone'
/var/www/discourse/lib/tasks/uploads.rake:401:in `block (2 levels) in <top (required)>'
/var/www/discourse/vendor/bundle/ruby/2.3.0/gems/rails_multisite-1.0.6/lib/rails_multisite/connection_management.rb:126:in `block in each_connection'
/var/www/discourse/vendor/bundle/ruby/2.3.0/gems/rails_multisite-1.0.6/lib/rails_multisite/connection_management.rb:124:in `each'
/var/www/discourse/vendor/bundle/ruby/2.3.0/gems/rails_multisite-1.0.6/lib/rails_multisite/connection_management.rb:124:in `each_connection'
/var/www/discourse/lib/tasks/uploads.rake:401:in `block in <top (required)>'
/usr/local/bin/bundle:22:in `load'
/usr/local/bin/bundle:22:in `<main>'
Tasks: TOP => uploads:recover_from_tombstone
(See full trace by running task with --trace)

Is this a bug or a problem with my installation?