Last week I had a lot of issues with DDG where it barely returned a single page for some development-related queries it shined on before. I am wondering if some

Last week I had a lot of issues with DDG where it barely returned a single page for some development-related queries it shined on before. I am wondering if something went wrong with their algorithms? I also periodically observed disappearance and reappearance of certain sites as a result of the same query (and not just different ranking, but them either completely vanishing from the results or you could get to them at some point).