STA Beacon Report gives you an idea of all the APs that the client is able to see so the AP/Controller based on the information provided (Signal/SNR/etc) it will determine the right AP to move the client to.
HS-1-Choir 10.14.1.18 d8:c7:c8:4d:f1:60 WDC-Member -76 Jun 25 03:22:19 Jun 25 03:22:19 6/0 S
HS-Comm-NW 10.14.0.41 d8:c7:c8:4d:eb:40 WDC-Member -73 Jun 25 03:23:58 Jun 24 21:04:02 1/0 S
HS-1-Office-W 10.14.0.27 6c:f3:7f:a5:a9:00 WDC-Member -45 Jun 25 08:33:25 Jun 24 18:02:58 11/3 *
HS-Comm-NE 10.14.0.42 d8:c7:c8:4d:ec:20 WDC-Member -77 Jun 25 03:26:15 Jun 24 21:04:02 11/2 S
HS-1-Forum-S 10.14.0.13 d8:c7:c8:4e:16:60 WDC-Member -71 Jun 24 21:04:50 Jun 24 21:04:02 1/0 S
HS-Comm-NC 10.14.0.38 d8:c7:c8:4d:ec:c0 WDC-Member -80 Jun 25 03:26:14 Jun 24 21:04:02 11/0 S
And looking at that log the controller didn't find a better AP compare to the one the client is currently attach to :
HS-1-Office-W 10.14.0.27 6c:f3:7f:a5:a9:00 WDC-Member -45 "has the better signal"
"For client f0:7b:cb:a4:35:72 Trigger Sticky No better candidate AP"
" Client Match: Skip steer for client f0:7b:cb:a4:35:72 from 6c:f3:7f:a5:a9:02"