Adding a chapter to a work in a series does not move the series to the top of the user's Series page

How to replicate:

1) As a user with multiple series, edit a work in a series that is not your most recent series
2) Add a chapter to that work
3) Go to your Series page (e.g., https://archiveofourown.org/users/testy/series)
4) Wait

What should happen:

The newly-updated series should move to the top of your series page.

What does happen:

The date in the upper right corner of the blurb updates, but the series stays stubbornly where it is, as though you had not updated it.

Other notes:

Adding a new work to a series will bring it to the top; it's only new chapters that don't. For testing, also try removing a chapter to see if the series moves back down.