rake convert / jq convert error

Wether rake convert nor the jq variant does work:

$ bundle exec rake convert --trace                                                                                                                                                                           329ms  Thu 20:59
** Invoke convert (first_time)
** Execute convert
rake aborted!
Dashboard file 0299630a-cb7a-54aa-916e-a259dd2222cd.json is missing the dashboard key
/home/doerflt/repos/git/gitlab.com/grafana-dashboards/Rakefile:93:in `block (2 levels) in <top (required)>'
/home/doerflt/repos/git/gitlab.com/grafana-dashboards/Rakefile:83:in `each'
/home/doerflt/repos/git/gitlab.com/grafana-dashboards/Rakefile:83:in `block in <top (required)>'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/task.rb:281:in `block in execute'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/task.rb:281:in `each'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/task.rb:281:in `execute'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/task.rb:219:in `block in invoke_with_call_chain'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/task.rb:199:in `synchronize'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/task.rb:199:in `invoke_with_call_chain'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/task.rb:188:in `invoke'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/application.rb:160:in `invoke_task'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/application.rb:116:in `block (2 levels) in top_level'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/application.rb:116:in `each'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/application.rb:116:in `block in top_level'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/application.rb:125:in `run_with_threads'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/application.rb:110:in `top_level'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/application.rb:83:in `block in run'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/application.rb:186:in `standard_exception_handling'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/lib/rake/application.rb:80:in `run'
/usr/share/rubygems-integration/all/gems/rake-13.0.6/exe/rake:27:in `<top (required)>'
/usr/bin/rake:25:in `load'
/usr/bin/rake:25:in `<main>'
Tasks: TOP => convert

With jq:

jq .dashboard dashboards/gitaly-fleet-overview.json > import/import-gitaly-fleet-overview.json && cat import/import-gitaly-fleet-overview.json                                                                     Thu 21:01
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