Util::JSON.dump receives non-hash options

Puppet Version: Main branch (401e01b2691d9c496749ff07f7fca7fc852e105c)
Puppet Server Version: Main branch (38479aafcb6c27d826976e31a993258e9e9e4de2)
OS Name/Version: Ubuntu 20.04

While testing the file_metadatas Puppetserver endpoint, when sending this request:
code
https://localhost:8140/puppet/v3/file_metadatas/scripts/mymodule/script.sh?environment=production&recurse=yes
code
Puppet errors with (apologies for the backtrace!):
code
2021-09-03 07:58:27,688 DEBUG [qtp1541353205-57] [puppetserver] Puppet Could not render_multiple to Puppet::Network::Format[json]: undefined method `delete' for #<JSON::Ext::Generator::State:0x79067448>
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/util/json.rb:64:in `dump'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/format_support.rb:105:in `to_json'
json/ext/GeneratorMethods.java:79:in `to_json'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/util/json.rb:65:in `dump'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/formats.rb:129:in `render_multiple'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/format_support.rb:26:in `render_multiple'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/api/indirected_routes.rb:161:in `block in do_search'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/api/indirected_routes.rb:192:in `block in first_response_formatter_for'
org/jruby/RubyEnumerable.java:690:in `find'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/api/indirected_routes.rb:190:in `first_response_formatter_for'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/api/indirected_routes.rb:160:in `do_search'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/api/indirected_routes.rb:53:in `block in call'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/context.rb:62:in `override'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet.rb:306:in `override'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/api/indirected_routes.rb:52:in `call'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/api/server/v3.rb:17:in `block in wrap'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/route.rb:82:in `block in process'
org/jruby/RubyArray.java:1809:in `each'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/route.rb:81:in `process'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/route.rb:88:in `process'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/route.rb:88:in `process'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/handler.rb:86:in `block in process'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/handler.rb:69:in `block in with_request_profiling'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/util/profiler/around_profiler.rb:58:in `profile'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/util/profiler.rb:51:in `profile'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/handler.rb:65:in `with_request_profiling'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/handler.rb:85:in `block in process'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/handler.rb:92:in `respond_to_errors'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/network/http/handler.rb:84:in `process'
uri:classloader:/puppetserver-lib/puppet/server/master.rb:69:in `block in handleRequest'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet/context.rb:62:in `override'
/home/lucy/githubs/puppetserver/ruby/puppet/lib/puppet.rb:306:in `override'
uri:classloader:/puppetserver-lib/puppet/server/master.rb:68:in `handleRequest'
code

This only happens when requesting the scripts mount - the request
code
https://localhost:8140/puppet/v3/file_metadatas/modules/mymodule/file?environment=production&recurse=yes
code
behaves as expected.

The object that dump is receiving in this case actually can be converted to a hash, and adding
code
options = options.to_h unless options.is_a?(Hash)
code
fixes the issue, but doesn't really get to why this method is receiving the wrong object to begin with.

Happy to provide more testing and info!