Hello there,
i have one big problem with clients on my routerboard 433 - ROS 5.16, with dcma-81 cards. I had the same problem when i was on PC with 2.9.27, with tplink atheros cards.
Edimax 7206APG with 1.32 firmware whole time reassociates with my routerboard.. and all the clients which have that model of router.. what to do or is there no help?
.. maximum time of connected router is ~ 5 min. - can’t go more.. 
Thank you!