Hi everyone. I've had the weirdest glitch happen in my game- I've tried posting help to r/sims2help, but the only thing that's come of that so far is that other people have apparently had this problem. I figured posting here wouldn't be the worst idea, either... Forgive me if I've posted this in the wrong section or something, this is my first time using any of MTS's forums.

So I open up Pleasantview, head to the SSU college hood, and go to open up Lilith and Dirk's dorm. Everything is fine, until I open up her relationships tab and Dirk is missing. Like, she doesn't know him at all. Her memories related to him are still there (i.e. went steady with Dirk, snuck out with Dirk, etc), but according to the relationships tab she's never met him before. However, in Dirk's relationships tag, she's still there, still his BFF/love interest. In fact, when I send her over to talk to him, it fulfills his want of meeting a new person, and then he immediately cries because he's lost her as a best friend since her side of the relationship is now at 0.
I am not sure exactly when this happened, only that I didn't notice it until I opened their household and looked into Lilith's relationships.
Is this a sign of corruption or something? I looked at the hood with hoodchecker, and it seemed fine, but then again I really have no idea how to use tools like hoodchecker and SimPE. The other people who've had this error on reddit have corrected it with sim blender, will that just make things fine again? But why did this happen in the first place?

I'm not really a computer person so I don't really know if I'm answering this part correctly, but here are my system specs:
What operating system you are running. - Windows 10
Your processor's type and speed. - Intel(R) Core(TM) i5-9300H CPU @ 2.30GHz
The amount of RAM you have. - 8.00 GB (7.85 GB usable)
The type of graphics card you have - brand, model number, RAM, and driver version. - I am not sure how to find this information. According to google my computer has a Nvidia GeForce GTX 1650?

Again, sorry if someone's answered this already or this post is in the wrong place.
Thanks for all your help.

This just happens very rarely and is not a sign of corruption or anything, it seems to be just a normal hickup. Fixing it with Sim Blender or any other mod and forgetting about it seems the best choice. I had a sim forget her fiancé once.

Using HoodChecker is pretty easy, you press the Remove button to fix all minor issues, then run a check again to see if anything is left. Ideally you wouldn't see anything at all. I always have four missing character warnings from downloaded NPCs (Multi PT hack) and nothing else, which means my hood is doing fine.

Thanks so much!
Usually when I open HoodChecker I get a handful of things like "Neither sim exists: (#) has relationship with (#)", "Invalid relationship with self: (name)" and "First sim does not exist: (#) has relationship with (name)" I just kind of figured that these minor errors were normal results of gameplay, since TS2 is kinda funky in general, and that I should just run hoodchecker on it and everything would be good. But should there be something I should be doing to keep these from popping up in the first place?

No, those are entirely normal. As long as HoodChecker can remove them, everything's fine.