Partnered Sims turn into siblings

Started playing a legacy save a few months ago.  I play with only MCCC occasionally, but have played this save without mods for the last few weeks and I play with no CC. 

The couple in question are a same sex couple with one child, not a science baby or adopted, it's their child, and one of them has skillful sleep, which seems to be key, and don't think I'll let any future same sex couples have skillful sleep again.  Their child just aged up to teen, and shortly after I noticed that they no longer had any romance options.  Went into their relationship and it shows them as siblings, as well as married etc.  I had gone into CAS after their child aged up to fix various things, as we do, and I'm guessing that is when this happened.

Went looking in the forum here for an answer, only to find out this has been an issue for years, but also from reading through this thread, seems to have become a much bigger and more widespread issue in the last few months and yet it appears EA isn't even looking at this thread!

I am beyond annoyed and frustrated that this issue has persisted for so long, that it seems to affect only same sex sims and yet silence from EA.  I've tried EA's fixes with repairing and starting a new file and moving the save into it, but nope, it's still an issue.

EA you need to do better and actually look at this issue!  I want to be able to play sims representative of me, and you seem to want to make sure of the same from that recent survey, and yet when I play a same sex couples, which is representative of me, there is a major freaking glitch, that does not seem to affect opposite sex couples!  Do better!

Just in case it's helpful for figuring out the problem I've attached the link to my save file.

https://drive.google.com/file/d/1Wx5lN_5bQVn8frnR2PbuhlSixsdv2kVW/view?usp=sharing 

I'm not holding my breath but would appreciate hearing from someone that EA is actually looking into this issue, since it is so game breaking for so many people!!