False positive PhanTypePossiblyInvalidDimOffset after array_key_exists

[mdeweerd]

PhanTypePossiblyInvalidDimOffset Possibly invalid offset 'inputko' of $input of array type array{name?:null|string,value?:string,values?:string[],default?:string,label?:string,type?:string,size?:string,morecss?:string,moreattr?:string,style?:string,inputko?:int}

                    if (array_key_exists('inputko', $input) && $input['inputko'] == 1 && isset($input['name'])) {
                        array_push($inputko, $input['name']); 
                    }

I hoped that the array_key_exists test would validate that the 'inputko' offset is ok.

Phan 5.4.3
php-ast version 1.0.16
PHP version used to run Phan: 8.1.13