@mitcho, first, thanks for your assistance! I know these requests (especially after 3.4) can be overwhelming! Great job!
About the maximum, I know it will sound weird but this morning it seems to be working fine. Is it possible that, although I did not flush it before going to bed, during the night the cache was updated?
About the $related_query-> references, YARPP did not work without removing all $related_query-> references (it took forever and tried to show the same related post entry infinite times). Should I leave it without the references?