Content item, sitepackage and delivered assets
Check fluid outputs of images and reloaded content items. Lack of space reservation in a reusable partial often affects many pages.
Limit the bottleneck to a specific element or resource. In TYPO3 projects, sitepackage, content elements and extensions can independently bring in additional scripts or large media; cache emptying alone does not remove this burden.
Where to check the setting in TYPO3
Assign the affected resource to the sitepackage or an extension. Compare the HTML of a simple content page to the slow detail page. Then check fluid image output, integrated assets and cache behavior of the responsible component.
Example of this specific finding
Illustrative control case: When loading an advertising space, the article slides downwards. The shifted text element is measured, but the missing space reservation is on the banner above it.
follow-up audit in TYPO3
Under the same measurement conditions, compare the affected side and a side without the suspicious element. After a change, cached and first uncached responses also differ.
Track the layout shift recording up to the triggering element. Reserve space in advance and also test consent banners, fonts and reloaded content.
Derogations and scope
A single laboratory measurement does not describe all user states. Classify targeted user interactions and late shifts separately.
Reference: TYPO3 13.4 with EXT:seo. For other major versions and own extensions, responsibilities may differ; check the actually installed output.
Classify the general error
Definition, system-independent causes and further correction examples: The shifting element is not always the cause