"The proxy server is refusing connections" after Tor has bootstrapped

Sometimes Tor Browser shows "The proxy server is refusing connections" after Tor has bootstrapped successfully:

    And the Tor Browser loads the startup page (failed)                                                                                                            # features/step_definitions/browser.rb:478
      try_for() timeout expired (Timeout::Error)
      ./features/support/helpers/misc_helpers.rb:145:in `rescue in try_for'
      ./features/support/helpers/misc_helpers.rb:51:in `try_for'
      ./features/step_definitions/browser.rb:204:in `page_has_loaded_in_the_tor_browser'
      ./features/step_definitions/browser.rb:494:in `/^the Tor Browser loads the (startup page|Tails homepage|Tails GitLab)$/'
      features/torified_browsing.feature:99:in `And the Tor Browser loads the startup page'
      #<Class:0x00007f6cade0ae40> (#<Class:0x00007f6cade0ae40>)
      ./features/support/helpers/misc_helpers.rb:74:in `block (2 levels) in try_for'
      ./features/support/helpers/misc_helpers.rb:66:in `loop'
      ./features/support/helpers/misc_helpers.rb:66:in `block in try_for'
      ./features/support/helpers/misc_helpers.rb:65:in `try_for'
      ./features/step_definitions/browser.rb:204:in `page_has_loaded_in_the_tor_browser'
      ./features/step_definitions/browser.rb:494:in `block in <top (required)>'

We have not ruled out that this might be a real issue affecting users.

The last journal entry with identifiers "Tor" or "tor" from an affected test run [1]:

Mar 22 22:48:21 amnesia Tor[8620]: Bootstrapped 100% (done): Done
[...]
Mar 22 22:48:37 amnesia onion-grater[4388]: 10.200.1.2:45186 (filter: tor-browser) connected: loaded filter: tor-browser
Mar 22 22:48:38 amnesia Tor[8620]: New control connection opened from 127.0.0.1.

I couldn't find anything else relevant in the journal.

Failed test suite runs:

Edited by anonym
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