NoMethodError: undefined method `linked_proposals' for nil:NilClass
  decidim/proposals/notify_proposals_mentioned_job.rb:8:in `perform'
    linked_proposals = proposal_metadata.linked_proposals
  active_job/execution.rb:39:in `block in perform_now'
    perform(*arguments)
  active_support/callbacks.rb:109:in `block in run_callbacks'
    env.value = !env.halted && (!block_given? || yield)
  new_relic/agent/instrumentation/active_job.rb:50:in `perform'
    block.call
  new_relic/agent/instrumentation/active_job.rb:22:in `block (3 levels) in <top (required)>'
    ::NewRelic::Agent::Instrumentation::ActiveJobHelper.perform(job, block)
...
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undefined method `linked_proposals' for nil:NilClass