When marking an update set as complete, ServiceNow selects the most recent default update set as the new current set. ServiceNow determines the default update set by searching for an update set starting with the word Default. Any update set starting with the word Default is therefore a possible default update set. The logic that chooses the most current default update set does not exclude ignored update sets. Thus if you have an ignored update set starting with the word Default, it may be selected as your current update set instead of the actual default update set.
Rename any ignored update sets starting with Default to start with something else.
For example, if your ignored update set is Default forms update v1.0, rename it to Update default forms v1.0.