Rubro pathfinding seems to rely on spawning marker entities at each location it tries to pathfind towards, these markers spawn at alarming rates and there is no code that handles their despawning.
This causes issues when the number of marker entities cross a certain treshold (depends on server hardware, but generally starts becoming noticeable around the range of tens of thousands)

This is something that I overlooked when developing the mod. Thank you for bringing it to my attention! Will be patched the next update.