[{reqId}] {exception_url}   PHP Notice: Undefined index: counter

from /srv/parsoid-testing/src/Parsoid.php(491)
#0 /srv/parsoid-testing/src/Parsoid.php(491): MWExceptionHandler::handleError(integer, string, string, integer, array)
#1 /srv/mediawiki/php-1.42.0-wmf.4/includes/Rest/Handler/ParsoidHandler.php(752): Wikimedia\Parsoid\Parsoid->pb2pb(MediaWiki\Parser\Parsoid\Config\PageConfig, string, Wikimedia\Parsoid\Core\PageBundle, array)
#2 /srv/mediawiki/php-1.42.0-wmf.4/includes/Rest/Handler/TransformHandler.php(131): MediaWiki\Rest\Handler\ParsoidHandler->wt2html(MediaWiki\Parser\Parsoid\Config\PageConfig, array, string)
#3 /srv/mediawiki/php-1.42.0-wmf.4/includes/Rest/Router.php(536): MediaWiki\Rest\Handler\TransformHandler->execute()
#4 /srv/mediawiki/php-1.42.0-wmf.4/includes/Rest/Router.php(441): MediaWiki\Rest\Router->executeHandler(MWParsoid\Rest\Handler\TransformHandler)
#5 /srv/mediawiki/php-1.42.0-wmf.4/includes/Rest/EntryPoint.php(195): MediaWiki\Rest\Router->execute(MediaWiki\Rest\RequestFromGlobals)
#6 /srv/mediawiki/php-1.42.0-wmf.4/includes/Rest/EntryPoint.php(135): MediaWiki\Rest\EntryPoint->execute()
#7 /srv/mediawiki/php-1.42.0-wmf.4/rest.php(31): MediaWiki\Rest\EntryPoint::main()
#8 /srv/mediawiki/w/rest.php(3): require(string)
#9 {main}