Hello,
By any chance do you have an external memory to support all of the data stored? I believe your problem will be most likely related for not having enough space in your device for all the nodes information.
Please consider that the memory of the device it's impacted for both the stack and your application size, once taking both into account, you will need to consider the different data to be stored of every node which.
The solution will be most likely to add an external memory so you can handle all the nodes information or consider adding more routers to the network.
Regards,
Estephania