Also your logs are in Winbox, saves screen area for this forum. (LOG is maintained in the Mikrotik until reboot)
The only thing I see is normal reconnects. (But one device in the access list, the others are default.) No refusal to reconnect.
The “unicast key exchange timeout” may be a problem that last longer than the reconnect. It looks as if your 2.4GHz band has a lot of interference. Did you check the channel usage, before picking channel 1,6 or 11? Tools “Freq usage”, and “Wireless Snooper” will help “see” the environment you are in.
http://forum.mikrotik.com/t/rb951g-2hnd-unicast-key-exchange-timeout/104896/1