What gameplay feature is this bug affecting?
den page mutation counter

What's the issue? Please include any error messages you receive and as much detail as possible.
this morning, right after I rolled over, my mutation counter read as 11. later in the day, I IBF'ed a lioness of mine, and she gave birth to 1 cub. I glanced at my mutation counter again a little while after this, and it now read as 12. suspicious, I checked the cub that came from the IBF'ed lioness, and it did in fact have an AMP. this AMP was completely random and no breeding items were used on the mother, and the mother's fertility is 43%

I have checked my entire pride to be sure that I haven't skipped over any mutated nursing cubs, and I am fairly certain that I'm not. using the search feature accessible through crossroads (which DOES show nursing mutated cubs), with my ID input as the owner, and "exclude dead" + "any mutation" checked, there are 10 lions that show up. we can add 1 more to include my king, who is a piebald. that leaves us at 11 mutated lions, while the counter on my page reads 12.

also worth noting that I have several other weaned AMP cubs in my pride currently who were all IBF'ed and had a GMO cow (some also had CRB stacked with the GMO) used on the mother. none of these cubs show up in the mutation counter, or in search

Any links relating to this bug? For example, if a particular lion is bugging, what is the link to that lion?
the AMP cub: https://www.lioden.com/lion.php?id=794204473791
(this cub was aged up to 1y 11m on the same day it was born)

Any screenshots you can provide us with?
n/a

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:
1. rollover, check mutation counter. it reads as 11 (I have 9 muts visible through that counter, 1 nursing pie cub, and 1 for my pie king)
2. about 5 hours later, IBF a lioness who has 1 cub
3. glance at the mutation counter again, it now reads as 12 (I did not happen to check the counter again immediately after the IBF, this was maybe 2 hours later)
4. check the cub that resulted from the IBF for a mutation. it does, in fact, have an AMP