Answer
IFS's own 'Global Context As-Delivered' layer is what gets automatically refreshed by R&D as part of an update itself, so IFS-delivered Aurena pages generally continue pointing at valid, current resources right after an update. However, any customer configuration layered on top of either the Global Context or a Custom/Named Context, functionally the same mechanism either way, sits above that as-delivered layer and isn't automatically reconciled by the update process — an update can leave that configuration layer referencing objects that changed or were removed, surfacing as errors on the affected pages. The only way to resolve this is manually revisiting each affected page's configuration after applying an update, verifying and fixing the specific broken reference, or reverting that piece of configuration back to the current as-delivered version. There's no officially published document detailing exactly which objects are affected by a given update; anecdotally, a larger jump across more update levels at once tends to surface more of these dangling-reference issues than a smaller single-update jump.