While undoing file captions I get internal error, e.g. in case of undoing this change I got [XbCuwQpAICwAAK60wekAAACP] 2019-10-23 19:49:21: Fatal exception of type "InvalidArgumentException". Tested on three different files, seems to be very fresh issue. Rollbacking works as expected.
2019-10-23 19:49:21 [XbCuwQpAICwAAK60wekAAACP] mw1323 commonswiki 1.35.0-wmf.3 exception ERROR: [XbCuwQpAICwAAK60wekAAACP] /w/index.php?title=File:Scorpio2.jpg&action=mcrundo&undo=367895766&undoafter=345858690&uselang=en InvalidArgumentException from line 3276 of /srv/mediawiki/php-1.35.0-wmf.3/includes/Revision/RevisionStore.php: Unsaved revision passed {"exception_id":"XbCuwQpAICwAAK60wekAAACP","exception_url":"/w/index.php?title=File:Scorpio2.jpg&action=mcrundo&undo=367895766&undoafter=345858690&uselang=en","caught_by":"mwe_handler"}
[Exception InvalidArgumentException] (/srv/mediawiki/php-1.35.0-wmf.3/includes/Revision/RevisionStore.php:3276) Unsaved revision passed
#0 /srv/mediawiki/php-1.35.0-wmf.3/includes/diff/DifferenceEngine.php(1470): MediaWiki\Revision\RevisionStore->countRevisionsBetween(MediaWiki\Revision\MutableRevisionRecord, MediaWiki\Revision\RevisionStoreCacheRecord, integer)
#1 /srv/mediawiki/php-1.35.0-wmf.3/includes/diff/DifferenceEngine.php(998): DifferenceEngine->getMultiNotice()
#2 /srv/mediawiki/php-1.35.0-wmf.3/includes/actions/McrUndoAction.php(242): DifferenceEngine->getDiff(string, string)
#3 /srv/mediawiki/php-1.35.0-wmf.3/includes/actions/McrUndoAction.php(374): McrUndoAction->generateDiffOrPreview()
#4 /srv/mediawiki/php-1.35.0-wmf.3/includes/htmlform/fields/HTMLInfoField.php(25): McrUndoAction->{closure}(array)
#5 /srv/mediawiki/php-1.35.0-wmf.3/includes/htmlform/HTMLForm.php(1699): HTMLInfoField->getDefault()
#6 /srv/mediawiki/php-1.35.0-wmf.3/includes/htmlform/HTMLForm.php(1299): HTMLForm->displaySection(array, string)
#7 /srv/mediawiki/php-1.35.0-wmf.3/includes/htmlform/OOUIHTMLForm.php(254): HTMLForm->getBody()
#8 /srv/mediawiki/php-1.35.0-wmf.3/includes/htmlform/HTMLForm.php(1076): OOUIHTMLForm->getBody()
#9 /srv/mediawiki/php-1.35.0-wmf.3/includes/htmlform/HTMLForm.php(1055): HTMLForm->getHTML(boolean)
#10 /srv/mediawiki/php-1.35.0-wmf.3/includes/htmlform/HTMLForm.php(606): HTMLForm->displayForm(boolean)
#11 /srv/mediawiki/php-1.35.0-wmf.3/includes/actions/FormAction.php(143): HTMLForm->show()
#12 /srv/mediawiki/php-1.35.0-wmf.3/includes/actions/McrUndoAction.php(90): FormAction->show()
#13 /srv/mediawiki/php-1.35.0-wmf.3/includes/MediaWiki.php(514): McrUndoAction->show()
#14 /srv/mediawiki/php-1.35.0-wmf.3/includes/MediaWiki.php(304): MediaWiki->performAction(ImagePage, Title)
#15 /srv/mediawiki/php-1.35.0-wmf.3/includes/MediaWiki.php(967): MediaWiki->performRequest()
#16 /srv/mediawiki/php-1.35.0-wmf.3/includes/MediaWiki.php(530): MediaWiki->main()
#17 /srv/mediawiki/php-1.35.0-wmf.3/index.php(44): MediaWiki->run()
#18 /srv/mediawiki/w/index.php(3): require(string)
#19 {main}