I ran into an exception while trying to call an NPC that I edited, wasn't sure if this was something that could be fixed or not but I've noticed the NPC also cannot be found by looking for them.
I'm sorry, but an uncaught exception occurred.
While running game code:
File "renpy/common/000statements.rpy", line 609, in execute_call_screen
store._return = renpy.call_screen(name, *args, **kwargs)
File "game/system.rpy", line 4267, in execute
File "game/system.rpy", line 4267, in execute
File "game/system.rpy", line 4269, in execute
File "game/system.rpy", line 4446, in execute
File "game/system.rpy", line 4566, in execute
File "game/system.rpy", line 4567, in execute
File "game/system.rpy", line 4568, in execute
File "game/system.rpy", line 4569, in execute
File "game/system.rpy", line 4569, in <module>
ValueError: invalid literal for int() with base 10: ''