When you move the members tab of a household record from the last position, it changes the default sub tab of the personal info tab to constituencies in individual records. Then when you move the personal tab back to the default location, the members tab of household records goes back to the last position.
If a user changes the sequence of the tabs for household records, it will impact for the individual records and vice versa. We don't have a separate design for individual and household records. For example, if we change the membership tab sequence on household records it changes the tab sequence for individual records to.
Steps to Duplicate
From Household record, move the members tab up in order
Go to an individual record and see that the personal info tab now opens to constituencies instead of personal.