I can’t address that specific arrow but it might be informative to understand what you are looking at. These are not connections. As I understand it, each node keeps a record of its neighbors, the nodes that it can see and there is a strong signal.
The green lines represent those two nodes list each other as a neighbor. the red arrows means that only the node the arrow is coming from lists the node that it’s pointing to as a neighbor but not the other way. That doesn’t mean that the nodes are connected to each other or that necessarily that messages sent from that node is necessarily relayed by one of those neighbors. It just means those two nodes have a strong signal between them and they see each other.
For example, node 66 is listed as a neighbor by a number of nodes but it does not report any neighbors itself (I’d guess it’s battery powered).
None of this explains why node 1 would list itself as a neighbor not not list itself as a neighbor (which is a contradiction) but that’s what that red arrow means. Something is fishy but perhaps it’s just benign.
No - I don’t think it’s anything to do with the node 255. I’m not really sure why this is shown like this, but it also doesn’t really matter. This is all just for information and as Rich points out just shows the information from the neighbour tables - all routing is still completed by the controller.