When personalizing a list layout, it will generate the sys_ui_list record in whatever the current session active scope is. This results in two or more sys_ui_list records matching the coalesce strategy, but having different scopes, which will generate a Skipped Error during upgrade.
1) Make sure you are in the Global scope.
2) Go to cab_agenda_item (or any non-globally-scoped table).
3) Personalize the list layout.
Observe the generated sys_ui_list record is in the Global scope instead of the table specific scope.
Pre-early-London list personalization used to incorrectly generate sys_update_name records. This issue does not occur in currently supported versions.
If an instance was upgraded and still shows this problem, the cause is old data still present in the sys_update_xml table for personalized lists. Cleaning it up will resolve the issue.