AOE4 Editor custom layout editor draw river bug crash Windows

When using custom layout editor draw river like the pics below,my Windows system will crash,making me have to reboot my computer.
Description: First,draw two parallel rivers(called river 0 and River 1).Second,draw the 3rd river by beginning in river 0,ending in river(called River 2).Third,draw the 4st river by beginning at river 3rd’s ending and ending at river 0.
This kind of costum rivers can’t be generate correctly. Unfortunately,it also crush my computer system almost every time.
Please fix it.
BTW,what is the rivers’ “layer” means(the number pin beside the river,in the official document called layer)?Is that only a tag to distinguish different rivers?If so,what the “send to back”“send backward”“bring forward”“bring to front” Tools use for?

Thank you for the report @CHNTuner. The Content Editor team will take a look.

Unfortunately, I’m not exactly sure on a use case for layers within the editor (I’ve not played with it yet), but hopefully this will be covered by any forthcoming documentation.