Assert failed: "false" in file serviceprovider.cpp:202

assert failed: "false" in file serviceprovider.cpp:202

This usually means that some service (adding a shop or teleport to an npc that usually wouldn't or won't accept it) was being rejected and will work again once it is removed.

This can also happen or have a similar error when tasks (quests) in/out are added to an npc that usually does not have them.

Note: For shops you can try and remove specific items through trial and error (some seem to trigger this error, but it hasn't been confirmed as to which)