Can't migrate uploads to S3

Hi, we’ve set up upload hosting (using the S3 settings) on Backblaze.
New uploads are working (after the x-amz-checksum-crc32 header fix), however trying to migrate existing uploads with uploads:migrate_to_s3 fails immediately.

This is on the latest Discourse version (3.5.0.beta5-dev).
Here is the full output:

root@goactuary-app:/var/www/discourse# rake uploads:migrate_to_s3 --trace                                                                                                                  
** Invoke uploads:migrate_to_s3 (first_time)                                                                                                                                               
** Invoke environment (first_time)                                                                                                                                                         
** Execute environment                                                                                                                                                                     
** Execute uploads:migrate_to_s3                                                                                                                                                           
Please note that migrating to S3 is currently not reversible!                                                                                                                              
[CTRL+c] to cancel, [ENTER] to continue                                                                                                                                                    
                                                                                                                                                                                           
Migrating uploads to S3 for 'default'...
Some uploads were not migrated to the new scheme. Running the migration, this may take a while...
rake aborted!                                                                                                                                                                              
FileStore::ToS3MigrationError: Some uploads could not be migrated to the new scheme. You need to fix this manually. (FileStore::ToS3MigrationError)
/var/www/discourse/lib/file_store/to_s3_migration.rb:156:in `migrate_to_s3'       
/var/www/discourse/lib/file_store/to_s3_migration.rb:59:in `migrate'                                                                                                                       
/var/www/discourse/lib/tasks/uploads.rake:126:in `migrate_to_s3'                                                                                                                           
/var/www/discourse/lib/tasks/uploads.rake:106:in `block in migrate_to_s3_all_sites'                                                                                                        
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-6.1.0/lib/rails_multisite/connection_management/null_instance.rb:49:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-6.1.0/lib/rails_multisite/connection_management/null_instance.rb:36:in `each_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-6.1.0/lib/rails_multisite/connection_management.rb:21:in `each_connection'
/var/www/discourse/lib/tasks/uploads.rake:104:in `migrate_to_s3_all_sites'                                                                                                                 
/var/www/discourse/lib/tasks/uploads.rake:100:in `block in <main>'                                                                                                                         
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/task.rb:281:in `block in execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/task.rb:281:in `each'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/task.rb:281:in `execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/task.rb:219:in `block in invoke_with_call_chain'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/task.rb:199:in `synchronize'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/task.rb:199:in `invoke_with_call_chain'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/task.rb:188:in `invoke' 
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/application.rb:188:in `invoke_task'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/application.rb:138:in `block (2 levels) in top_level'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/application.rb:138:in `each'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/application.rb:138:in `block in top_level'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/application.rb:147:in `run_with_threads'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/application.rb:132:in `top_level'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/application.rb:83:in `block in run'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/application.rb:214:in `standard_exception_handling'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.2.1/lib/rake/application.rb:80:in `run'
bin/rake:13:in `<top (required)>'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli/exec.rb:59:in `load'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli/exec.rb:59:in `kernel_load' 
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli/exec.rb:23:in `run'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli.rb:452:in `exec'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/vendor/thor/lib/thor/command.rb:28:in `run'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/vendor/thor/lib/thor/invocation.rb:127:in `invoke_command'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/vendor/thor/lib/thor.rb:538:in `dispatch'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli.rb:35:in `dispatch'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/vendor/thor/lib/thor/base.rb:584:in `start'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli.rb:29:in `start'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/exe/bundle:28:in `block in <top (required)>'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/friendly_errors.rb:117:in `with_friendly_errors'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/exe/bundle:20:in `<top (required)>'
/usr/local/bin/bundle:25:in `load'
/usr/local/bin/bundle:25:in `<main>'
Tasks: TOP => uploads:migrate_to_s3