From the log you posted, I notice a few things (maybe relevant, maybe not).
- the "main" troublemaker is clearly the device with MAC 10:27:F5:BC:3D:7C, in the snippet you posted it has some 170 disconnections/connections, while all the other devices have 2, 4 or 6
- the disconnection messages are different, the device above has ALL of them "unicast key exchange timeout", whilst the other ones have either of "received deauth" or "received disassoc"
- a "same" device when disconnected (and reconnected) multiple times has always the "same " disconnection message
The "unicast key exchange timeout" seemingly means "wrong password", see:
The “disconnected, received disassoc: sending station leaving (8)” and the "received disassoc: sending station leaving (8)" could be almost anything, but they appear to be originated by the stations (clients), maybe the issues with MAC 10:27:F5:BC:3D:7C saturate the cAP Lite and makes it not responding, and then the client decides to disconnect and try again.
The MAC 10:27:F5 seems to be a TP-Link device, can you detail which one?
(anecdata only, but after having used in the SAME spot a WA801ND, and then a WA901ND for years I upgraded to a WA1201 and the trouble began, untill I took the plunge and installed OpenWRT on it and everything went back to normal.)
For troubleshooting, I would add a "GrayWiFI" SSID and add to it only the MAC 10:27:F5:BC:3D:7C device and see what happens.