Error: Typed property Parser::$mOutputType must not be accessed before initialization

Backtrace:

from /data/mediawiki/workdir/includes/parser/Parser.php(4176)
#0 /data/mediawiki/workdir/includes/parser/Parser.php(1581): Parser->finalizeHeadings(string, string, boolean)
#1 /data/mediawiki/workdir/includes/parser/Parser.php(808): Parser->internalParse(string, boolean, boolean)
#2 /data/mediawiki/workdir/extensions/PageForms/includes/PF_FormPrinter.php(2134): Parser->recursiveTagParse(string)
#3 /data/mediawiki/workdir/extensions/PageForms/includes/PF_FormPrinter.php(1048): PFFormPrinter::getParsedValue(Parser, string)
#4 [internal function]: PFFormPrinter->formHTML(string, boolean, boolean, integer, NULL, NULL, NULL, integer, array, MediaWiki\User\User)
#5 /data/mediawiki/workdir/includes/StubObject/StubObject.php(125): call_user_func_array(array, array)
#6 /data/mediawiki/workdir/includes/StubObject/StubObject.php(155): MediaWiki\StubObject\StubObject->_call(string, array)
#7 /data/mediawiki/workdir/extensions/PageForms/specials/PF_RunQuery.php(92): MediaWiki\StubObject\StubObject->__call(string, array)
#8 /data/mediawiki/workdir/extensions/PageForms/specials/PF_RunQuery.php(34): PFRunQuery->printPage(string, boolean)
#9 /data/mediawiki/workdir/includes/specialpage/SpecialPage.php(727): PFRunQuery->execute(string)
#10 /data/mediawiki/workdir/includes/specialpage/SpecialPageFactory.php(1621): MediaWiki\SpecialPage\SpecialPage->run(string)
#11 /data/mediawiki/workdir/includes/MediaWiki.php(357): MediaWiki\SpecialPage\SpecialPageFactory->executePath(string, RequestContext)
#12 /data/mediawiki/workdir/includes/MediaWiki.php(960): MediaWiki->performRequest()
#13 /data/mediawiki/workdir/includes/MediaWiki.php(613): MediaWiki->main()
#14 /data/mediawiki/workdir/index.php(50): MediaWiki->run()
#15 /data/mediawiki/workdir/index.php(46): wfIndexMain()
#16 {main}