TYPO3 Core

I have found another error related to the patch for bug #44270.
If you have a $content parameter for substituteMarkerArrayCached which has no marker at all, then an empty result is given back. This is wrong. The full $content must be returned.
Do not store into the cache with substMarkerCache if the result of preg_match_all is 0 or FALSE or $usedMarkers is empty. This will solve this issue.

$storeArr['c'] = preg_split($regex, $content);
                $storeArr['k'] = $keyList[0];
            }

if (!empty($storeArr)) {
                // Setting cache:
                $this->substMarkerCache[$storeKey] = $storeArr;
                // Storing the cached data:
                $GLOBALS['TSFE']->sys_page->storeHash($storeKey, serialize($storeArr), 'substMarkArrayCached');
                $GLOBALS['TT']->setTSlogMessage('Parsing', 0);
            }
        }
    } else {
        // Unserializing
        $storeArr = unserialize($storeArrDat);
        // Setting cache:
        $this->substMarkerCache[$storeKey] = $storeArr;

The $content must be returned without any change if no marker is inside of it.

if (
            isset($storeArr['k'])
        ) {
            $content = '';
            // Traversing the keyList array and merging the static and dynamic content
            foreach ($storeArr['k'] as $n => $keyN) {
                $content .= $storeArr['c'][$n];
                if (!is_array($valueArr[$keyN])) {
                    $content .= $valueArr[$keyN];
                } else {
                    $content .= $valueArr[$keyN][intval($wSCA_reg[$keyN]) % 2];
                    $wSCA_reg[$keyN]++;
                }
            }
            $content .= $storeArr['c'][count($storeArr['k'])];
            $GLOBALS['TT']->pull();
        }

return $content;
    }

see
https://forge.typo3.org/issues/44270#change-289881