NOTE: this is on the web version. When I add a task to the smartlist using the same location, but from the account that "owns" it, it works fine and the shared task is seen on the other users shared list.

Hi Erik,
Thanks for getting in touch. You've encountered a specific combination of features/behaviors! 😅

Shared locations are supposed to work this way: when they are shared with you, you can see them, but cannot add to them. (You would see this more clearly from the location view or Smart Add/edit location views, where assigning the location wouldn't be available.)

However, the behavior of adding a property from a Smart List is kind of an implicit version of that, and doesn't limit the location in the same way. But as with an ambiguous Smart List (for example location:Work or location:Home) it's just silently not set (but in this case sets/unsets unexpectedly!).

I've added this to our list to investigate. Sorry for the inconvenience there! I'll keep you posted what we figure out.

Appreciate the response. Although this is a definitive location in the smartlist ("location is XXX" and nothing else), this technique seems to break down when it is not "my" location. It works great for the user who "owns" the location. Also, I can manually add the location by editing the task, but since it is too easy to forget this step I may work around by using a tag instead. Thanks.