[OPEN] Partnered Sims turn into siblings

[thecharsims]

@EA_Illium Yes, confirming that this issue still exists. I've already created a bug report for this topic a while back. I know you wanted info from users who didn't create threads yet but I wanted to chime in just bcus my error started way before the recent patch. I also sent my save to Sim Guru Nick a few weeks back when he asked if anyone could. He mentioned that his team was able to replicate the family tree glitch through someone else's save file though. Hoping for a fix soon.
Anyway, I play on PC. W10. I've had this family tree glitch long before Snowy Escape. It's been several months actually but I can't say specifically when my issue with this error occurred. I do know that I've had this glitch since sometime last year though. I do use cc/mods, however, I was able to replicate this glitch without them and I have never cloned my sims. Currently, I can't go into cas with my save bcus it'll break the family tree again if I do. Hoping this info helps aid in the restoration of all our family trees.

[ongoingwhy]

Product: The Sims 4
Platform:PC
Which language are you playing the game in? English
How often does the bug occur? Every time (100%)
What is your current game version number? 1.69.59.1020
What expansions, game packs, and stuff packs do you have installed? Seasons, Get Together, City Living, Spa Day, Parenthood, Vampires, Realm of Magic, Fitness Stuff
Steps: How can we find the bug ourselves? I don't know.
What happens when the bug occurs? The sim couple are unable to use romantic interaction because they are suddenly related to each other. 
What do you expect to see? The sim couple should be able to perform romance interactions with each other.
Have you installed any customization with the game, e.g. Custom Content or Mods? Yes
Did this issue appear after a specific patch or change you made to your system? Yes
Please describe the patch or change you made. 1.69.59.1020

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This issue started occurring since 1.69.59.1020 was installed. I've tried removing my mods and repairing the game files but the issue persists. I was able to fix it temporarily when I cleared all relationships of the sims. However, the bug re-appeared some time later while I was playing. I am unsure what triggered it.

Summary: Sim A is married to Sim B. Sim A suddenly became Sim B's niece. Sim A has a daughter who also became Sim B's niece.

Edit By Crinrict: Remove tag. Please don't tag your own posts except with pack tags or I will miss processing it assuming I already that.

[crinrict]

@ongoingwhy Does it happen with all your sims or just a specific couple ?

Did you delete the localthumbcache file after removing mods ?

[ongoingwhy]

@crinrictI am only playing with a single household for this save. It only affects the couple. They can still use romantic interactions with other sims. The issue persists after deleting localthumbcache and removing the mods. I will test whether it will trigger again on an older save with mods removed.

Edit: I figured out what's the issue. I checked my save and sim A became the aunt of sim B even though they were married. Sim B, who was supposed to be the stepmother of sim C, became her aunt as well. For some reason, it was showing up correctly in the family tree. I managed to clear it with MCCC but I will test whether it triggers again.

[crinrict]

@ongoingwhy So similar to this: https://answers.ea.com/t5/Bug-Reports/NEEDS-INFO-Partnered-Sims-turn-into-siblings/td-p/8458978 ?

Do you still have a save from before you fixed it you could sent to EA ?

[ongoingwhy]

@crinrictIt's probably not the same issue. I tried to see whether entering CAS would trigger it earlier but it didn't. Sure, I have a save that still has the bug. How should I send it?

Edit: I think I know how this happened. I've been trying to set both sims A and B as the mothers of sim C with MCCC. I don't understand how the spouse ended up becoming the aunt though. The older save should have also been affected too.

[usshathaway]

@EA_Illium If it could be useful, I have a save file from right before the corruption occurs. Any time I use CAS in that save file, the corruption occurs. I can send you a copy of that save, if it could help your team find a fix.

[crinrict]

@ongoingwhy Nvm. I thought they needed saves for that but it seems I remembered that wrong. So all good.

[ongoingwhy]

@crinrictHmm, it's still triggering. Sim A is suddenly the niece of sim B again. I used MCCC earlier to clear all the relationships for both sims, so there should have been no problem. I've also noticed that sim A mysteriously gained an unknown parent in the family tree but this unknown parent is not related to sim B. I'll try to create parents for sim A to see if that solves this issue.

Edit: Creating a new parent for sim A doesn't solve the issue. I think the issue lies with sim B since both sims A and C are turning into her nieces.

[crinrict]

@ongoingwhy Does this happen if you don't do any editing at all as well ?