What gameplay feature is this bug affecting?
Nesting

What's the issue? Please include any error messages you receive and as much detail as possible.
I had 3 newly claimed lionesses. One has the snarky pose. I had all three open in separate tabs and bred to each one left to right, and repeated for the failed attempts. Then I tried to make them a nest and it consumed two nesting materials and several feathers, gave me the green conformation message ending in "Yay!!" But none of the three had nests.

It does seem that -completely different lionesses- who I intentionally didn't want to have a nest (trying to get the achievement for losing a litter) now magically have a nest- and I compared against my screenshot trying to recreate the bug and it is in fact a different lioness. (It filled all three of the lionesses who did not have a nest and had 1 day left to delivery.)

Any links relating to this bug? For example, if a particular lion is bugging, what is the link to that lion?
The lionesses that got the nest and shouldn't have (I think.) They were all named Newly Claimed Lioness and the three at the bottom of the stack had no nests.
https://www.lioden.com/lion.php?id=794166832722
https://www.lioden.com/lion.php?id=794166832754
https://www.lioden.com/lion.php?id=794166832825

The three that didn't get a nest:
*One has one now due to me trying to recreate the issue, but there were no past lionesses without a nest so it worked as intended this time.
https://www.lioden.com/lion.php?id=794166934232
https://www.lioden.com/lion.php?id=794166934283
https://www.lioden.com/lion.php?id=794166934290

Any screenshots you can provide us with?
Accessed from lioness's page (one that didn't get a nest) right after a successful breeding. Nesting material has not been selected.
https://cdn.discordapp.com/attachments/996825059228401744/1000747921328844860/ScreenShot_7_24_2022_7_46_36_AM.png

The selected nesting material.
https://cdn.discordapp.com/attachments/996825059228401744/1000747921723105332/ScreenShot_7_24_2022_7_46_42_AM.png

The results after confirming and committing to the nesting material.
https://cdn.discordapp.com/attachments/996825059228401744/1000747920829718638/ScreenShot_7_24_2022_7_46_45_AM.png

Pressed back to get back to lioness page, is not nesting. Upon refreshing, double checking list, she did not have a nest.
https://cdn.discordapp.com/attachments/996825059228401744/1000747921123315832/ScreenShot_7_24_2022_7_46_54_AM.jpg

No nest for new lionesses, nest applied to an older lioness:
https://cdn.discordapp.com/attachments/996825059228401744/1000748678430076979/ScreenShot_7_24_2022_7_50_16_AM.png

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:
(This is occurring in Unsorted lions) Edit: Sorry, that's "Pregnant Lionesses" list, not unsorted.
Have lionesses with one day remaining until birth that do not have a nest. Do not have auto nesting enabled on account. Obtain new lionesses that are added to unsorted via a Dreamboat male, so they are in heat. (Not sure if matters but one had a special pose.)

Breed them in separate tabs with only one attempt each, repeating left to right until all are pregnant. (There were 4 failures, two lionesses with two failed attempts each.)

Click the 'build a nest' text that appears on each lion, taking them each to a new page in their own tab. Build a nest for each of them left to right.

If done correctly, the nest should apply to the wrong lionesses that weren't in the tabs.

If you're able to replicate this bug, you deserve a prize from the prize chest- it seems ultra rare and ultra specific.