I know that the server went bonkers, but I thought I would let you know that I have a mare that is recently retired to brood but it still in my training summary. Here she is: https://www.finalfurlong.org/viewhorse.php?horse=24686
Clearly not urgent by any means, just odd.
Update: This mare is still hanging out on the training page even though she is listed as a broodmare. An additional discovery - If I try to put her into hypomating it says “The mare you are looking for cannot be found!” or something to that effect. 
Seems to be the same database updating situation reported here: Hypothetical Mating - Mare Not Found