I removed the whole Mods folder and deleted localthumbcache.package file as well.
I tried to open a fresh save and tested with the Thebe family. Before I go to world map and load any lot in build mode. Everything is fine. Both my secret and scandals of other Sims appear.
But after I load any lot in world mode and come back to Thebe family. From Princess Cordelia's perspective, only my secret still exists. Scandals from other Sims do not expose as you mentioned.
Can't duplicate this even on a new save. Still have both secrets after entering a lot from world map
Putting this on review though, maybe other see the same.
The Sims Team
