I've had this issue with the LLAMA but only rarely. In some worlds, like in Moonlight Falls where LLAMAs are EVERYWHERE, sims use them all the time and I never hear a peep about it. I always have the same mods installed and keep mostly the same Nraas settings and such, so I don't know what the variable could be that makes certain saves have complaints and others have none.

Except hmm, I almost never let my inactive sims buy cars. They tend to get around by taxi unless they had cars to begin with. I wonder if lacking their own transportation and being forced to use a taxi changes how the routing works?

The one save I for sure remember having the LLAMA error was an old save from before I knew how to disallow inactives from buying vehicles, so EVERYONE had their own car in that game.

I don't know if personal transportation could actually make a difference, but it would kinda make sense from my own experience with the GoHere/LLAMA kerfluffle.