TYPO3 Core

Using this code:

lib.content-singlepage = COA
lib.content-singlepage {
    10 = HMENU
    10 {
        includeNotInMenu = 1
        special = directory
        1 = TMENU
        1 {
            expAll = 1
            noBlur = 1
            NO = 1
            NO {
                doNotLinkIt = 1
                doNotShowLink = 1
                stdWrap2 { 
                    cObject = COA # this makes some trouble tho
                    cObject {
                        20 =< page.10 
                    }
                }
                wrapItemAndSub = |
            }
        }
    }
}

throws the following error:

PHP Warning: Undefined array key 1 in /var/www/html/public/typo3/sysext/frontend/Classes/ContentObject/Menu/TextMenuContentObject.php line 144

Bug reported by Tyrone Rogers on Slack: https://typo3.slack.com/archives/C025BQLFA/p1666274266356589