I've gotten this error since version 5.20a, both with and without mods.

1. Game version: 5.21 (happened in 5.20 too)
2. Your OS or if you are playing web version: Windows 10
3. Bug description: 

Error: Node not found: ../../..

At: scene/main/node.cpp.1524

1. Way to replicate it (if complex): Start a game, load a save.
2. Save file (if possible): Any and all

Thanks, Maverik! It's not a pressing issue and doesn't seem to affect gameplay, but don't want it to suddenly affect anything else.