Error while running event alt-alt-mode::on_selected_entity_changed (ID 59)
alt-alt-mode/scripts/util.lua:81: attempt to index field '?' (a nil value)
stack traceback:
alt-alt-mode/scripts/util.lua:81: in function <alt-alt-mode/scripts/util.lua:76>
[C]: in function 'sort'
alt-alt-mode/scripts/util.lua:76: in function 'sort_inventory'
alt-alt-mode/scripts/entity_logic.lua:751: in function '?'
alt-alt-mode/scripts/entity_logic.lua:1166: in function 'show_alt_info_for_entity'
alt-alt-mode/scripts/player_logic.lua:48: in function 'show_alt_info_for_player'
alt-alt-mode/control.lua:14: in function <alt-alt-mode/control.lua:9>

Thanks for the report.

For next time please provide some more information so I can more easily reproduce it.

In this case you were using a constant combinator with multiple sections. One section was from a logistic group where you set the quality to "Any Quality", and the other section had the same signal type with a different quality.

If that is not the case, please let me know, because I've fixed the above bug.

Sorry i could not recreate it myself and it happened randomly when i was scrolling the map.

Thanks for the fix, appriciate it!

Yes, makes sense. It's quite an obscure bug.
Luckily I was able to figure it out based on the stacktrace, so that was hugely appreciated.

Hope you didn't lose too much playtime.