Internal error

From MicrobeWiki, the student-edited microbiology resource

[61fd01fbf3d634b356909b2f] /index.php?title=General_Microbiology_by_Students_of_Jennifer_Bhatnagar,_Boston_University&oldid=155420 InvalidArgumentException: Actor name can not be empty for 0 and 3962

Backtrace:

from /var/lib/mediawiki/includes/user/ActorStore.php(168)
#0 /var/lib/mediawiki/includes/Revision/RevisionStore.php(1801): MediaWiki\User\ActorStore->newActorFromRowFields()
#1 [internal function]: MediaWiki\Revision\RevisionStore->MediaWiki\Revision\{closure}()
#2 /var/lib/mediawiki/includes/Revision/RevisionStoreCacheRecord.php(104): call_user_func()
#3 /var/lib/mediawiki/includes/Revision/RevisionStoreCacheRecord.php(78): MediaWiki\Revision\RevisionStoreCacheRecord->loadFreshRow()
#4 /var/lib/mediawiki/includes/Revision/RevisionRecord.php(511): MediaWiki\Revision\RevisionStoreCacheRecord->getVisibility()
#5 /var/lib/mediawiki/includes/Revision/RevisionStoreRecord.php(136): MediaWiki\Revision\RevisionRecord->userCan()
#6 /var/lib/mediawiki/includes/Linker.php(1379): MediaWiki\Revision\RevisionStoreRecord->userCan()
#7 /var/lib/mediawiki/includes/page/Article.php(1605): Linker::revUserTools()
#8 /var/lib/mediawiki/includes/page/Article.php(637): Article->setOldSubtitle()
#9 /var/lib/mediawiki/includes/page/Article.php(528): Article->generateContentOutput()
#10 /var/lib/mediawiki/includes/actions/ViewAction.php(78): Article->view()
#11 /var/lib/mediawiki/includes/MediaWiki.php(542): ViewAction->show()
#12 /var/lib/mediawiki/includes/MediaWiki.php(322): MediaWiki->performAction()
#13 /var/lib/mediawiki/includes/MediaWiki.php(904): MediaWiki->performRequest()
#14 /var/lib/mediawiki/includes/MediaWiki.php(562): MediaWiki->main()
#15 /var/lib/mediawiki/index.php(50): MediaWiki->run()
#16 /var/lib/mediawiki/index.php(46): wfIndexMain()
#17 {main}