vBulletin: Importing announcements may crash

Exception trace:
  at <redacted>/src/XF/Str/Formatter.php:231
 XF\Cli\Runner->run() at <redacted>/cmd.php:17

In Formatter.php line 231:

  [TypeError]
  XF\Str\Formatter::replaceSmiliesHtml(): Argument #1 ($text) must be of type string, null given, called in <redacted>/src/XF/BbCode/Renderer/Html.php on line 441

Exception trace:
  at <redacted>/src/XF/Str/Formatter.php:231
 XF\Str\Formatter->replaceSmiliesHtml() at <redacted>/src/XF/BbCode/Renderer/Html.php:441...