Previously, unique identifiers for sockets were created automatically, sometimes using .001 and sometimes _001. Now they are created manually with the second format, but some files were saved with .001 format. I think this was only an issue in the vector math node. rBd845ba481c6d fixed this problem in 3.1, but in a more general way. After I merge this patch to 3.1, I will revert it, since the versioning added in that commit will make this redundant. Differential Revision: https://developer.blender.org/D13209