Mailbox no longer affects lot thumbnail

Okay, tl;dr version: The lot thumbnails in my game used to work correctly. Enter the lot, rotate the mailbox, exit the lot, the thumbnail has rotated. Now they don't.

I have a retail, registered, non-arr'd version of the game. I am patched up to 1.8 and do not have WA. I have Riverview. I have CAW installed and am using it regularly, but although I'm fuzzy on the timeline I know for sure the problem pre-dates the 1.8 patch (mostly because one of the reasons I finally patched was just in case it might, somehow, fix the problem). I'm running Windows XP on a PC which usually runs Sims 3 smoothly and with no issues. I don't know if system specs are relevant, but if so I will provide them.

Long version:
At some point, I do not know exactly when, but suspect it was around patch 1.5 or so, lot thumbnails in my game became static. Meaning, old lot thumbnails (from lots built before the problem began) ~~do not change from their current angle~~ which have had the mailbox rotated, and newly built lots are all from the same angle and do not ever change. (Originally I thought the older thumbnails didn't change. I was wrong. They change all right - to the same rotation as the new lots, no matter what the mailbox angle. It's as if the game is taking all lot thumbnails from a fixed point and does not recognize any other angles as valid.) I know that the thumbnails are actually updating, because if I make visible changes on the lot they will appear in the thumbnail immediately. This happens in all neighborhoods, including the one I am currently building.

I have been troubleshooting this issue for weeks. I have saved my game and tried it. I have used a backup and tried it. I have restarted my computer and tried it. I have removed all CC except hacks and tried it. I have removed all CC including hacks and tried it. I have removed my library and tried it. I have deleted all my caches, with my CC removed, and tried it. As far as I can tell, this is a problem I seem to be having with the plain, patched, base game. ~~The one thing I have not tried is re-installing the whole game, mostly because I am lazy. If I don't get any new info on the problem, I'm trying that next.~~ Okay, between the time I first posted this and now (a couple hours later), I went ahead and uninstalled/reinstalled, and I have confirmed - this is a patched base game problem. I reinstalled, tested a new neighborhood on a default family, and the lot thumbnail rotated fine. I then patched from base game up to 1.8 and tested again - the lot thumbnail system is now as broken as ever. I find it weird that in all the complaints about patch problems, nobody mentioned this particular issue. Which makes me still think there's something wrong with my setup or something I'm doing differently. I didn't try to patch and test from base game up, patch by patch sequentially in order to isolate the problem, because that would take forever and I have sleeping to do.

(There used to be an explanation of my CC here, but I have confirmed this is NOT a CC issue at all, so it's irrelevant now.)

I have searched Google. I have searched Mod the Sims. I have searched MATY. I have searched the Livejournal communities. I have found zero reports of this. Actually, when I search the only thing that comes up is the now obnoxious statement that rotating the mailbox determines your lot thumbnail, to which I *headdesk* a great deal because it doesn't anymore. Does anyone else have this problem? Am I seriously the only member of the entire Sims 3 community who is experiencing this?

I have a long history of troubleshooting and fixing Sims problems by myself with no issues, so I've actually waited a really long time to ask for help at all, mainly because it's embarrassing that I can't figure it out. I am very familiar with the Sims 2 and 3 troubleshooting process. This is the first time an issue has stumped me. Please, someone tell me I'm missing something glaringly obvious. Or at least confirm my suspicion that EAxis sucks and it's their fault.