I have seen others on Reddit and Facebook have also had this bug. I’ve shared the link to this post, hopefully someone will report to the right place. It’s definitely a shared experience.
I am also having this issue, although I have yet to test with a different sim. Save has never had mods installed. This sim is a vampire with the bat ability though - could that be connected?
EDIT: @crinrict does your sim live in the neighborhood? Because when I start a new save and place a sim in one of the empty houses and click Listen to Whispers, it works, but if I travel there, I get a route error.
this is happening with two separate sims in two different save files. both spellcasters. had a thought that it might be related to the discovery quests, but haven’t had a chance to test yet.
I only have the one young adult female in house with her Grimborn toddler at the moment. It's happening with that YA-F.
I'll try adding a couple more sims to their household as test subjects to see if this is specific to her. TBC
