More Awesome Than You!

I was working on my "20 Best Friends" LTW, and it was fulfilled when I got 19 best friends.  I counted, recounted, only 19 best friends in the relationship panel.

Counted up best friend memories, I had 21 of them, but 1 was a long deceased sim and the other was Mystery Sim, so really only 19.

Then I checked the memory for the LTW, and the icon was a bird cage.  There is a bird on my lot, and my sim talks to this bird often... but I had no idea they could become friends.  It seems really, really strange, but why on earth would my LTW memory icon show a bird cage?

Why do you assume the dead Sim isn't counted?
The LTW just checks how many "best friends" memories you have, not if these are for valid Sims. IIRC you can get it even with just one Sim, by losing and regaining the best friend status over and over.

it's just one of those funny sims things. like fulfilling the woohoo want in the photobooth, with the photobooth.  ???

IIRC the want is "20 simultaneous best friends", so you can't do it with one friend.

You're right. I was confusing this with the "big man on campus" want, which /does/ suffer from a counting problem due to this.

Indeed, no relationship flags are wiped at death: the dead sim does not show in the panel, but the mutual flags are recognized anyway. Friends, best friends, lovers, etc are all counted even if dead. They count for simultaneous loves, too, and the friend/best friend flag is wiped only by the regular relationship decay.
I call bug, because it causes issues in gameplay (sims with the fear of falling out of love, cheating widowers, etc.).

Dead lovers count?  Really?
I'm so going to make a femme fatale black widdow sim, with 20 dead husbands in the back yard, if that's true.

Yep. On several occasions, I've had the message "X and Y are no longer best friends" when Y had been dead for a while. So it appears that the relationship decays as normal after they're dead -- and until it has decayed, the dear departed is still counted as a best friend.

(Hasn't happened in a while now: it's possible that some hack I've installed stops it happening, or otherwise that it simply didn't have a chance of happening.)

I believe a patch sorted it out - though it's most likely that they just stopped the message from appearing rather than wiping the flags at death.

Enemies Accumulate has a fix that halts the rel decay of dead people, preventing weird effects from manifesting.

I knew that dead people could still count as best friends (I had seen that message pop up about them no longer being friends plenty of times before the patch) but this sim had been dead for a long time.  Probably close to 30 days.  Not sure how long it would take the relationship to decay though.
Still curious that the icon showed a birdcage, but I guess icons for memories can sometimes be pretty screwy.