In the past two days I have been getting a message - 'Component library updates available' - whenever I open my apps for editing. All the apps share a component, but the component has not been updated for 6 months. If I use the accompanying Review button to see what changes have been made in the component, it displays my last change from six months ago:

All the apps are updated regularly (several times a month) and this component update was applied shortly after it was made.
Has Microsoft changed something in the way that components are managed?