FWIW The Related Topics here on meta used to be 
It was my most favourite AI addition (hands-down 
)
It has gone a bit squiffy though and seems to be prioritising less useful topics. As a now casual browser, I can’t pinpoint exactly when it happened, but the difference does seem noticeable.
Do you know if the model was changed at any point, or maybe something else backend-wise that could have had an impact?