Scion and I are on PC's, running Windows 10.
I, with plugins, attempted to hit the list notes button on the Nav screen, sitting in Odia M-14. Scion's (pluginless) popup stated:

lua/iup/matrix.lua:54: bad argument #4 to 'MatrixSetCell' (string expected, got nil)
stack traceback:
vo/error:lua:71: in function <vo/error.lua:70>
[C]: in function 'MatrixSetCell'
lua/iup/matrix.lua:54: in function 'setcell'
vo/if_navmaptemplate.lua:321: in function 'reset_matrix'
vo/if_navmaptemplate.lua:321: in function 'list_notes'
vo/if_navmaptemplate.lua:321: in function <vo/if_navmaptemplate.lua:466>
(tail call): ?

Mine followed up with plugin information after that point. As far as I know, I don't have a note anywhere (why I pressed the button), however, Scion has MANY notes.

i am getting this error as well when i click on "List Notes"

stack traceback:
vo/error.lua:71: in function <vo/error.lua:70>
[C]: in function 'MatrixSetCell'
lua/iup/matrix.lua:54: in function 'setcell'
vo/if_navmaptemplate.lua:321: in function 'reset_matrix'
vo/if_navmaptemplate.lua:461: in function 'list_notes'
vo/if_navmaptemplate.lua:468: in function <vo/if_navmaptemplate.lua:466>
(tail call): ?

i do not use navcomp or navroute, but i do have extensive notes throughout the 'verse.

Just to give a little more information from doing a little digging. It seems this error crops up if there are any notes saved to a system notes file that has an ID that is not an actual system ID. I removed all my system notes and plugins that write to system notes and this error went away.

Not sure if the plan is to allow these plugins to continue to write to files that are not actually using a system ID, but that is what seems to be causing this.

Keep in mind, that this is just my own thoughts and opinions on what is going on. I obviously have no way of being sure of this.

This should be fixed now.