A bunch of these showed up after deploying 1.36.0-wmf.28 to group0:
Sample url: www.mediawiki.org/w/load.php?lang=fr&modules=ext.echo.styles.badge%7Cext.uls.pt%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Coojs-ui.styles.icons-alerts%7Cskins.vector.styles.legacy&only=styles&skin=vector
ErrorException: PHP Notice: Undefined offset: 1
The offset varies. Values between 1 and 6 were seen.
from /srv/mediawiki/php-1.36.0-wmf.28/includes/libs/objectcache/MediumSpecificBagOStuff.php(1094)
#0 /srv/mediawiki/php-1.36.0-wmf.28/includes/libs/objectcache/MediumSpecificBagOStuff.php(1094): MWExceptionHandler::handleError(integer, string, string, integer, array)
#1 /srv/mediawiki/php-1.36.0-wmf.28/includes/libs/objectcache/RedisBagOStuff.php(282): MediumSpecificBagOStuff->updateOpStats(string, array, array)
#2 /srv/mediawiki/php-1.36.0-wmf.28/includes/libs/objectcache/MediumSpecificBagOStuff.php(617): RedisBagOStuff->doSetMulti(array, integer, integer)
#3 /srv/mediawiki/php-1.36.0-wmf.28/includes/resourceloader/dependencystore/KeyValueDependencyStore.php(84): MediumSpecificBagOStuff->setMulti(array, integer, integer)
#4 /srv/mediawiki/php-1.36.0-wmf.28/includes/resourceloader/ResourceLoader.php(613): Wikimedia\DependencyStore\KeyValueDependencyStore->storeMulti(string, array, integer)
#5 /srv/mediawiki/php-1.36.0-wmf.28/includes/deferred/MWCallableUpdate.php(38): ResourceLoader->{closure}()
#6 /srv/mediawiki/php-1.36.0-wmf.28/includes/deferred/DeferredUpdates.php(513): MWCallableUpdate->doUpdate()
#7 /srv/mediawiki/php-1.36.0-wmf.28/includes/deferred/DeferredUpdates.php(390): DeferredUpdates::attemptUpdate(MWCallableUpdate, Wikimedia\Rdbms\LBFactoryMulti)
#8 /srv/mediawiki/php-1.36.0-wmf.28/includes/deferred/DeferredUpdates.php(221): DeferredUpdates::run(MWCallableUpdate, Wikimedia\Rdbms\LBFactoryMulti, Monolog\Logger, BufferingStatsdDataFactory, string)
#9 /srv/mediawiki/php-1.36.0-wmf.28/includes/deferred/DeferredUpdatesScope.php(267): DeferredUpdates::{closure}(MWCallableUpdate, integer)
#10 /srv/mediawiki/php-1.36.0-wmf.28/includes/deferred/DeferredUpdatesScope.php(196): DeferredUpdatesScope->processStageQueue(integer, integer, Closure)
#11 /srv/mediawiki/php-1.36.0-wmf.28/includes/deferred/DeferredUpdates.php(242): DeferredUpdatesScope->processUpdates(integer, Closure)
#12 /srv/mediawiki/php-1.36.0-wmf.28/includes/MediaWiki.php(1117): DeferredUpdates::doUpdates(string)
#13 /srv/mediawiki/php-1.36.0-wmf.28/includes/MediaWiki.php(853): MediaWiki->restInPeace()
#14 /srv/mediawiki/php-1.36.0-wmf.28/includes/MediaWiki.php(865): MediaWiki->{closure}()
#15 /srv/mediawiki/php-1.36.0-wmf.28/load.php(56): MediaWiki->doPostOutputShutdown()
#16 /srv/mediawiki/php-1.36.0-wmf.28/load.php(38): wfLoadMain()
#17 /srv/mediawiki/w/load.php(3): require(string)
#18 {main}