What gameplay feature is this bug affecting?
past cubs page

What's the issue? Please include any error messages you receive and as much detail as possible.
instead of showing the correct sire, my former king Spinifex, it shows my current king, Dibello. affects both Spinifex and the lionesses' past cubs page.

Any links relating to this bug? For example, if a particular lion is bugging, what is the link to that lion?
Scallop's list for example.
https://www.lioden.com/cubs.php?id=794226923843
The pariah stud is correct, Dibello is obviously not. this is further proven by looking at the cub, Mao:
https://www.lioden.com/lion.php?id=794229193978
Who's sire/father is correctly listed as Spinifex.

here's Spinifex's page, just to display what the bug looks like on a former king's page.
https://www.lioden.com/cubs.php?id=794182582970

Any screenshots you can provide us with?

Obviously not the right sire!
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The example with Mao:



Please provide us with step by step explanation how this bug happened so we can attempt to replicate it. If it's complex, please include screenshots where possible:
Retire your king while he has living cubs, choose a new king, then look at the cubs bred list of the former king or a lioness he was bred to. i retired spinifex the moment he was able to do so without the fee- maybe that contributes?