@onept8tee 

Hello, it appears that the signal strength obtained from the furthest one does not reach the threshold value which failed to trigger the roaming between different APs/bands. That is why it switches to the furthest one.

Usually, we can move them further away from each other, or try to disable mesh technology of the specific device to turn off seamless roaming between Decos for this client. While please notice that it won't block the roaming initialized by the client itself. You can read this article to get more information about fast roaming/mesh technology. 

Considering you have disabled mesh technology of the client, it seems that the roaming was initialized by the client itself.  Try to move them further away from each other and give it a go. 

Good day.