Lyra mesh network issues

[Titankid]

I set up a mesh network in my house (3 Asus Lyra AC2200 nodes), but i have encountered some problems which i hope you can help me with. 
 

I have the main node in my basement right beside my modem, one in the middle floor, and one in the top floor. If i am in the kitchen, or in the middle floor bathroom (in between two nodes), the wifi suddently just doesnt work... It says i have full signal, but nothing will load, not even speedtest. It often works again after i turn wifi off and on, but it gets really annoying after a while. I suspect that, because i am in the middle of two nodes, the nodes struggle to know which node i should recieve wifi frow (if that made sense). 
 

The worst part is that sometimes, i can be just beside a node, and still get this instability issue. 
 

Has anyone experienced similar issues? Is there a way to fix this? I have googled arround but all i find is praise to how good Asus Lyra is... My modem is not in bridge mode, should it be?

 

(for information, i have 500/500 fiber, so bandwith is not the issue here, when the network works, the speed is awesome everywhere in the house)